diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index abe4b2b71dc8..7b17f9b8c66c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -75,19 +75,18 @@ jobs:
     - uses: actions/checkout@v2
       with:
         submodules: 'true'
-    - name: Install system packages
-      run: |
-        sudo apt-get install -y --no-install-recommends ninja-build
-    - uses: conda-incubator/setup-miniconda@v2
+    - uses: mamba-org/provision-with-micromamba@f347426e5745fe3dfc13ec5baf20496990d0281f # v14
       with:
-        auto-update-conda: true
-        python-version: ${{ matrix.python-version }}
-        activate-environment: test
+        cache-downloads: true
+        cache-env: true
+        environment-name: cpp_test
+        environment-file: tests/ci_build/conda_env/cpp_test.yml
     - name: Display Conda env
       shell: bash -l {0}
       run: |
         conda info
         conda list
+
     - name: Build and install XGBoost static library
       shell: bash -l {0}
       run: |
@@ -109,6 +108,7 @@ jobs:
         cd ..
         rm -rf ./build
         popd
+
     - name: Build and install XGBoost shared library
       shell: bash -l {0}
       run: |
diff --git a/.github/workflows/python_tests.yml b/.github/workflows/python_tests.yml
index 7ad742045223..cd88c25b7e2a 100644
--- a/.github/workflows/python_tests.yml
+++ b/.github/workflows/python_tests.yml
@@ -41,12 +41,46 @@ jobs:
       run: |
         python tests/ci_build/lint_python.py --format=0 --type-check=0 --pylint=1
 
+  python-sdist-test-on-Linux:
+    # Mismatched glibcxx version between system and conda forge.
+    runs-on: ${{ matrix.os }}
+    name: Test installing XGBoost Python source package on ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    steps:
+    - uses: actions/checkout@e2f20e631ae6d7dd3b768f56a5d2af784dd54791 # v2.5.0
+      with:
+        submodules: 'true'
+    - uses: mamba-org/provision-with-micromamba@f347426e5745fe3dfc13ec5baf20496990d0281f # v14
+      with:
+        cache-downloads: true
+        cache-env: false
+        environment-name: sdist_test
+        environment-file: tests/ci_build/conda_env/sdist_test.yml
+    - name: Display Conda env
+      shell: bash -l {0}
+      run: |
+        conda info
+        conda list
+    - name: Build and install XGBoost
+      shell: bash -l {0}
+      run: |
+        cd python-package
+        python --version
+        python setup.py sdist
+        pip install -v ./dist/xgboost-*.tar.gz
+        cd ..
+        python -c 'import xgboost'
+
   python-sdist-test:
+    # Use system toolchain instead of conda toolchain for macos and windows.
+    # MacOS has linker error if clang++ from conda-forge is used
     runs-on: ${{ matrix.os }}
     name: Test installing XGBoost Python source package on ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-11, windows-latest]
+        os: [macos-11, windows-latest]
         python-version: ["3.8"]
     steps:
     - uses: actions/checkout@v2
@@ -56,11 +90,7 @@ jobs:
       if: matrix.os == 'macos-11'
       run: |
         brew install ninja libomp
-    - name: Install Ubuntu system dependencies
-      if: matrix.os == 'ubuntu-latest'
-      run: |
-        sudo apt-get install -y --no-install-recommends ninja-build
-    - uses: conda-incubator/setup-miniconda@v2
+    - uses: conda-incubator/setup-miniconda@35d1405e78aa3f784fe3ce9a2eb378d5eeb62169 # v2.1.1
       with:
         auto-update-conda: true
         python-version: ${{ matrix.python-version }}
@@ -80,25 +110,26 @@ jobs:
         cd ..
         python -c 'import xgboost'
 
-  python-tests-on-win:
+  python-tests-on-macos:
     name: Test XGBoost Python package on ${{ matrix.config.os }}
     runs-on: ${{ matrix.config.os }}
+    timeout-minutes: 60
     strategy:
       matrix:
         config:
-          - {os: windows-latest, python-version: '3.8'}
+          - {os: macos-11}
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@e2f20e631ae6d7dd3b768f56a5d2af784dd54791 # v2.5.0
       with:
         submodules: 'true'
 
-    - uses: conda-incubator/setup-miniconda@v2
+    - uses: mamba-org/provision-with-micromamba@f347426e5745fe3dfc13ec5baf20496990d0281f # v14
       with:
-        auto-update-conda: true
-        python-version: ${{ matrix.config.python-version }}
-        activate-environment: win64_env
-        environment-file: tests/ci_build/conda_env/win64_cpu_test.yml
+        cache-downloads: true
+        cache-env: false
+        environment-name: macos_test
+        environment-file: tests/ci_build/conda_env/macos_cpu_test.yml
 
     - name: Display Conda env
       shell: bash -l {0}
@@ -106,35 +137,38 @@ jobs:
         conda info
         conda list
 
-    - name: Build XGBoost on Windows
+    - name: Build XGBoost on macos
       shell: bash -l {0}
       run: |
-        mkdir build_msvc
-        cd build_msvc
-        cmake .. -G"Visual Studio 17 2022" -DCMAKE_CONFIGURATION_TYPES="Release" -A x64 -DGOOGLE_TEST=ON  -DUSE_DMLC_GTEST=ON
-        cmake --build . --config Release --parallel $(nproc)
+        brew install ninja
+
+        mkdir build
+        cd build
+        # Set prefix, to use OpenMP library from Conda env
+        # See https://github.com/dmlc/xgboost/issues/7039#issuecomment-1025038228
+        # to learn why we don't use libomp from Homebrew.
+        cmake .. -GNinja -DCMAKE_PREFIX_PATH=$CONDA_PREFIX
+        ninja
 
     - name: Install Python package
       shell: bash -l {0}
       run: |
         cd python-package
         python --version
-        python setup.py bdist_wheel --universal
-        pip install ./dist/*.whl
+        python setup.py install
 
     - name: Test Python package
       shell: bash -l {0}
       run: |
-        pytest -s -v ./tests/python
+        pytest -s -v -rxXs --durations=0 ./tests/python
 
-  python-tests-on-macos:
+  python-tests-on-win:
     name: Test XGBoost Python package on ${{ matrix.config.os }}
     runs-on: ${{ matrix.config.os }}
-    timeout-minutes: 90
     strategy:
       matrix:
         config:
-          - {os: macos-11, python-version "3.8" }
+          - {os: windows-latest, python-version: '3.8'}
 
     steps:
     - uses: actions/checkout@v2
@@ -145,8 +179,8 @@ jobs:
       with:
         auto-update-conda: true
         python-version: ${{ matrix.config.python-version }}
-        activate-environment: macos_test
-        environment-file: tests/ci_build/conda_env/macos_cpu_test.yml
+        activate-environment: win64_env
+        environment-file: tests/ci_build/conda_env/win64_cpu_test.yml
 
     - name: Display Conda env
       shell: bash -l {0}
@@ -154,27 +188,23 @@ jobs:
         conda info
         conda list
 
-    - name: Build XGBoost on macos
+    - name: Build XGBoost on Windows
       shell: bash -l {0}
       run: |
-        brew install ninja
-
-        mkdir build
-        cd build
-        # Set prefix, to use OpenMP library from Conda env
-        # See https://github.com/dmlc/xgboost/issues/7039#issuecomment-1025038228
-        # to learn why we don't use libomp from Homebrew.
-        cmake .. -GNinja -DGOOGLE_TEST=ON -DUSE_DMLC_GTEST=ON -DCMAKE_PREFIX_PATH=$CONDA_PREFIX
-        ninja
+        mkdir build_msvc
+        cd build_msvc
+        cmake .. -G"Visual Studio 17 2022" -DCMAKE_CONFIGURATION_TYPES="Release" -A x64 -DGOOGLE_TEST=ON  -DUSE_DMLC_GTEST=ON
+        cmake --build . --config Release --parallel $(nproc)
 
     - name: Install Python package
       shell: bash -l {0}
       run: |
         cd python-package
         python --version
-        python setup.py install
+        python setup.py bdist_wheel --universal
+        pip install ./dist/*.whl
 
     - name: Test Python package
       shell: bash -l {0}
       run: |
-        pytest -s -v ./tests/python
+        pytest -s -v -rxXs --durations=0 ./tests/python
diff --git a/.github/workflows/r_tests.yml b/.github/workflows/r_tests.yml
index 6bc95941d250..6174ea92046d 100644
--- a/.github/workflows/r_tests.yml
+++ b/.github/workflows/r_tests.yml
@@ -5,6 +5,7 @@ on: [push, pull_request]
 env:
   R_PACKAGES: c('XML', 'data.table', 'ggplot2', 'DiagrammeR', 'Ckmeans.1d.dp', 'vcd', 'testthat', 'lintr', 'knitr', 'rmarkdown', 'e1071', 'cplm', 'devtools', 'float', 'titanic')
   GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+  _R_CHECK_EXAMPLE_TIMING_CPU_TO_ELAPSED_THRESHOLD_: 2.5
 
 permissions:
   contents: read # to fetch code (actions/checkout)
@@ -68,6 +69,7 @@ jobs:
           - {os: windows-latest, r: 'release', compiler: 'mingw', build: 'cmake'}
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
+      _R_CHECK_EXAMPLE_TIMING_CPU_TO_ELAPSED_THRESHOLD_: 2.5
       RSPM: ${{ matrix.config.rspm }}
 
     steps:
@@ -121,6 +123,10 @@ jobs:
         config:
           - {r: 'release'}
 
+    env:
+      _R_CHECK_EXAMPLE_TIMING_CPU_TO_ELAPSED_THRESHOLD_: 2.5
+      MAKE: "make -j$(nproc)"
+
     steps:
     - uses: actions/checkout@v2
       with:
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 64aeae29c737..b889b0767f34 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
-cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
-project(xgboost LANGUAGES CXX C VERSION 1.7.0)
+cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
+project(xgboost LANGUAGES CXX C VERSION 1.7.5)
 include(cmake/Utils.cmake)
 list(APPEND CMAKE_MODULE_PATH "${xgboost_SOURCE_DIR}/cmake/modules")
 cmake_policy(SET CMP0022 NEW)
@@ -27,7 +27,7 @@ set_default_configuration_release()
 #-- Options
 ## User options
 option(BUILD_C_DOC "Build documentation for C APIs using Doxygen." OFF)
-option(USE_OPENMP "Build with OpenMP support." ON)
+option(USE_OPENMP "Build with OpenMP support." OFF)
 option(BUILD_STATIC_LIB "Build static library" OFF)
 option(FORCE_SHARED_CRT "Build with dynamic CRT on Windows (/MD)" OFF)
 option(RABIT_BUILD_MPI "Build MPI" OFF)
@@ -168,11 +168,24 @@ find_package(Threads REQUIRED)
 
 if (USE_OPENMP)
   if (APPLE)
-    # Require CMake 3.16+ on Mac OSX, as previous versions of CMake had trouble locating
-    # OpenMP on Mac. See https://github.com/dmlc/xgboost/pull/5146#issuecomment-568312706
-    cmake_minimum_required(VERSION 3.16)
-  endif (APPLE)
-  find_package(OpenMP REQUIRED)
+    find_package(OpenMP)
+    if (NOT OpenMP_FOUND)
+      # Try again with extra path info; required for libomp 15+ from Homebrew
+      execute_process(COMMAND brew --prefix libomp
+                      OUTPUT_VARIABLE HOMEBREW_LIBOMP_PREFIX
+                      OUTPUT_STRIP_TRAILING_WHITESPACE)
+      set(OpenMP_C_FLAGS
+        "-Xpreprocessor -fopenmp -I${HOMEBREW_LIBOMP_PREFIX}/include")
+      set(OpenMP_CXX_FLAGS
+        "-Xpreprocessor -fopenmp -I${HOMEBREW_LIBOMP_PREFIX}/include")
+      set(OpenMP_C_LIB_NAMES omp)
+      set(OpenMP_CXX_LIB_NAMES omp)
+      set(OpenMP_omp_LIBRARY ${HOMEBREW_LIBOMP_PREFIX}/lib/libomp.dylib)
+      find_package(OpenMP REQUIRED)
+    endif ()
+  else ()
+    find_package(OpenMP REQUIRED)
+  endif ()
 endif (USE_OPENMP)
 #Add for IBM i
 if (${CMAKE_SYSTEM_NAME} MATCHES "OS400")
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 000000000000..f6d1aaa4461b
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,4 @@
+FROM azul/zulu-openjdk:8-latest
+RUN apt-get -y update && \
+    apt-get install -y build-essential cmake python3 git neovim maven python-is-python3 curl
+ENTRYPOINT ["/bin/bash"]
diff --git a/R-package/CMakeLists.txt b/R-package/CMakeLists.txt
index bf72bebde114..2c428cf32af6 100644
--- a/R-package/CMakeLists.txt
+++ b/R-package/CMakeLists.txt
@@ -31,7 +31,7 @@ if (USE_OPENMP)
 endif (USE_OPENMP)
 set_target_properties(
   xgboost-r PROPERTIES
-  CXX_STANDARD 14
+  CXX_STANDARD 17
   CXX_STANDARD_REQUIRED ON
   POSITION_INDEPENDENT_CODE ON)
 
diff --git a/R-package/DESCRIPTION b/R-package/DESCRIPTION
index 2f77f9734ad0..e1cef707d894 100644
--- a/R-package/DESCRIPTION
+++ b/R-package/DESCRIPTION
@@ -1,8 +1,8 @@
 Package: xgboost
 Type: Package
 Title: Extreme Gradient Boosting
-Version: 1.7.0.1
-Date: 2022-10-18
+Version: 1.7.5.1
+Date: 2023-03-29
 Authors@R: c(
   person("Tianqi", "Chen", role = c("aut"),
          email = "tianqi.tchen@gmail.com"),
@@ -66,5 +66,6 @@ Imports:
     methods,
     data.table (>= 1.9.6),
     jsonlite (>= 1.0),
-RoxygenNote: 7.1.1
-SystemRequirements: GNU make, C++14
+RoxygenNote: 7.2.3
+Encoding: UTF-8
+SystemRequirements: GNU make, C++17
diff --git a/R-package/LICENSE b/R-package/LICENSE
index b9f38c38aaf9..bc1c21d59fe5 100644
--- a/R-package/LICENSE
+++ b/R-package/LICENSE
@@ -1,9 +1,9 @@
-Copyright (c) 2014 by Tianqi Chen and Contributors 
+Copyright (c) 2014-2023, Tianqi Chen and XBGoost Contributors
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
-    
+
    http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
diff --git a/R-package/R/callbacks.R b/R-package/R/callbacks.R
index d5c69f52d3a8..fa947346937d 100644
--- a/R-package/R/callbacks.R
+++ b/R-package/R/callbacks.R
@@ -544,9 +544,11 @@ cb.cv.predict <- function(save_models = FALSE) {
 #'
 #' @return
 #' Results are stored in the \code{coefs} element of the closure.
-#' The \code{\link{xgb.gblinear.history}} convenience function provides an easy way to access it.
+#' The \code{\link{xgb.gblinear.history}} convenience function provides an easy
+#' way to access it.
 #' With \code{xgb.train}, it is either a dense of a sparse matrix.
-#' While with \code{xgb.cv}, it is a list (an element per each fold) of such matrices.
+#' While with \code{xgb.cv}, it is a list (an element per each fold) of such
+#' matrices.
 #'
 #' @seealso
 #' \code{\link{callbacks}}, \code{\link{xgb.gblinear.history}}.
@@ -558,7 +560,7 @@ cb.cv.predict <- function(save_models = FALSE) {
 #' # without considering the 2nd order interactions:
 #' x <- model.matrix(Species ~ .^2, iris)[,-1]
 #' colnames(x)
-#' dtrain <- xgb.DMatrix(scale(x), label = 1*(iris$Species == "versicolor"))
+#' dtrain <- xgb.DMatrix(scale(x), label = 1*(iris$Species == "versicolor"), nthread = 2)
 #' param <- list(booster = "gblinear", objective = "reg:logistic", eval_metric = "auc",
 #'               lambda = 0.0003, alpha = 0.0003, nthread = 2)
 #' # For 'shotgun', which is a default linear updater, using high eta values may result in
@@ -583,14 +585,14 @@ cb.cv.predict <- function(save_models = FALSE) {
 #'
 #' # For xgb.cv:
 #' bst <- xgb.cv(param, dtrain, nfold = 5, nrounds = 100, eta = 0.8,
-#'              callbacks = list(cb.gblinear.history()))
+#'               callbacks = list(cb.gblinear.history()))
 #' # coefficients in the CV fold #3
 #' matplot(xgb.gblinear.history(bst)[[3]], type = 'l')
 #'
 #'
 #' #### Multiclass classification:
 #' #
-#' dtrain <- xgb.DMatrix(scale(x), label = as.numeric(iris$Species) - 1)
+#' dtrain <- xgb.DMatrix(scale(x), label = as.numeric(iris$Species) - 1, nthread = 2)
 #' param <- list(booster = "gblinear", objective = "multi:softprob", num_class = 3,
 #'               lambda = 0.0003, alpha = 0.0003, nthread = 2)
 #' # For the default linear updater 'shotgun' it sometimes is helpful
diff --git a/R-package/R/xgb.Booster.R b/R-package/R/xgb.Booster.R
index 2f1f5091cdf2..f31c506466f9 100644
--- a/R-package/R/xgb.Booster.R
+++ b/R-package/R/xgb.Booster.R
@@ -328,8 +328,9 @@ predict.xgb.Booster <- function(object, newdata, missing = NA, outputmargin = FA
                                 predleaf = FALSE, predcontrib = FALSE, approxcontrib = FALSE, predinteraction = FALSE,
                                 reshape = FALSE, training = FALSE, iterationrange = NULL, strict_shape = FALSE, ...) {
   object <- xgb.Booster.complete(object, saveraw = FALSE)
+
   if (!inherits(newdata, "xgb.DMatrix"))
-    newdata <- xgb.DMatrix(newdata, missing = missing)
+    newdata <- xgb.DMatrix(newdata, missing = missing, nthread = NVL(object$params[["nthread"]], -1))
   if (!is.null(object[["feature_names"]]) &&
       !is.null(colnames(newdata)) &&
       !identical(object[["feature_names"]], colnames(newdata)))
diff --git a/R-package/R/xgb.DMatrix.R b/R-package/R/xgb.DMatrix.R
index 3aade2396d0f..b843d651833a 100644
--- a/R-package/R/xgb.DMatrix.R
+++ b/R-package/R/xgb.DMatrix.R
@@ -18,7 +18,7 @@
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #' xgb.DMatrix.save(dtrain, 'xgb.DMatrix.data')
 #' dtrain <- xgb.DMatrix('xgb.DMatrix.data')
 #' if (file.exists('xgb.DMatrix.data')) file.remove('xgb.DMatrix.data')
@@ -110,7 +110,7 @@ xgb.get.DMatrix <- function(data, label = NULL, missing = NA, weight = NULL, nth
 #' @examples
 #' data(agaricus.train, package='xgboost')
 #' train <- agaricus.train
-#' dtrain <- xgb.DMatrix(train$data, label=train$label)
+#' dtrain <- xgb.DMatrix(train$data, label=train$label, nthread = 2)
 #'
 #' stopifnot(nrow(dtrain) == nrow(train$data))
 #' stopifnot(ncol(dtrain) == ncol(train$data))
@@ -138,7 +138,7 @@ dim.xgb.DMatrix <- function(x) {
 #' @examples
 #' data(agaricus.train, package='xgboost')
 #' train <- agaricus.train
-#' dtrain <- xgb.DMatrix(train$data, label=train$label)
+#' dtrain <- xgb.DMatrix(train$data, label=train$label, nthread = 2)
 #' dimnames(dtrain)
 #' colnames(dtrain)
 #' colnames(dtrain) <- make.names(1:ncol(train$data))
@@ -193,7 +193,7 @@ dimnames.xgb.DMatrix <- function(x) {
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #'
 #' labels <- getinfo(dtrain, 'label')
 #' setinfo(dtrain, 'label', 1-labels)
@@ -249,7 +249,7 @@ getinfo.xgb.DMatrix <- function(object, name, ...) {
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #'
 #' labels <- getinfo(dtrain, 'label')
 #' setinfo(dtrain, 'label', 1-labels)
@@ -345,7 +345,7 @@ setinfo.xgb.DMatrix <- function(object, name, info, ...) {
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #'
 #' dsub <- slice(dtrain, 1:42)
 #' labels1 <- getinfo(dsub, 'label')
@@ -401,7 +401,7 @@ slice.xgb.DMatrix <- function(object, idxset, ...) {
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #'
 #' dtrain
 #' print(dtrain, verbose=TRUE)
diff --git a/R-package/R/xgb.DMatrix.save.R b/R-package/R/xgb.DMatrix.save.R
index e11b793b7d4b..91edb32d0c94 100644
--- a/R-package/R/xgb.DMatrix.save.R
+++ b/R-package/R/xgb.DMatrix.save.R
@@ -7,7 +7,7 @@
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #' xgb.DMatrix.save(dtrain, 'xgb.DMatrix.data')
 #' dtrain <- xgb.DMatrix('xgb.DMatrix.data')
 #' if (file.exists('xgb.DMatrix.data')) file.remove('xgb.DMatrix.data')
diff --git a/R-package/R/xgb.create.features.R b/R-package/R/xgb.create.features.R
index f00ac9314ce8..98b03ea8a984 100644
--- a/R-package/R/xgb.create.features.R
+++ b/R-package/R/xgb.create.features.R
@@ -48,8 +48,8 @@
 #' @examples
 #' data(agaricus.train, package='xgboost')
 #' data(agaricus.test, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
-#' dtest <- with(agaricus.test, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
+#' dtest <- with(agaricus.test, xgb.DMatrix(data, label = label, nthread = 2))
 #'
 #' param <- list(max_depth=2, eta=1, silent=1, objective='binary:logistic')
 #' nrounds = 4
@@ -65,8 +65,12 @@
 #' new.features.test <- xgb.create.features(model = bst, agaricus.test$data)
 #'
 #' # learning with new features
-#' new.dtrain <- xgb.DMatrix(data = new.features.train, label = agaricus.train$label)
-#' new.dtest <- xgb.DMatrix(data = new.features.test, label = agaricus.test$label)
+#' new.dtrain <- xgb.DMatrix(
+#'   data = new.features.train, label = agaricus.train$label, nthread = 2
+#' )
+#' new.dtest <- xgb.DMatrix(
+#'   data = new.features.test, label = agaricus.test$label, nthread = 2
+#' )
 #' watchlist <- list(train = new.dtrain)
 #' bst <- xgb.train(params = param, data = new.dtrain, nrounds = nrounds, nthread = 2)
 #'
@@ -79,7 +83,7 @@
 #'           accuracy.after, "!\n"))
 #'
 #' @export
-xgb.create.features <- function(model, data, ...){
+xgb.create.features <- function(model, data, ...) {
   check.deprecation(...)
   pred_with_leaf <- predict(model, data, predleaf = TRUE)
   cols <- lapply(as.data.frame(pred_with_leaf), factor)
diff --git a/R-package/R/xgb.cv.R b/R-package/R/xgb.cv.R
index c07d452c1522..a7c009db6329 100644
--- a/R-package/R/xgb.cv.R
+++ b/R-package/R/xgb.cv.R
@@ -110,9 +110,9 @@
 #'
 #' @examples
 #' data(agaricus.train, package='xgboost')
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 #' cv <- xgb.cv(data = dtrain, nrounds = 3, nthread = 2, nfold = 5, metrics = list("rmse","auc"),
-#'                   max_depth = 3, eta = 1, objective = "binary:logistic")
+#'              max_depth = 3, eta = 1, objective = "binary:logistic")
 #' print(cv)
 #' print(cv, verbose=TRUE)
 #'
@@ -192,7 +192,7 @@ xgb.cv <- function(params=list(), data, nrounds, nfold, label = NULL, missing =
 
   # create the booster-folds
   # train_folds
-  dall <- xgb.get.DMatrix(data, label, missing)
+  dall <- xgb.get.DMatrix(data, label, missing, nthread = params$nthread)
   bst_folds <- lapply(seq_along(folds), function(k) {
     dtest  <- slice(dall, folds[[k]])
     # code originally contributed by @RolandASc on stackoverflow
diff --git a/R-package/R/xgb.plot.tree.R b/R-package/R/xgb.plot.tree.R
index dc2656170222..a11790c25329 100644
--- a/R-package/R/xgb.plot.tree.R
+++ b/R-package/R/xgb.plot.tree.R
@@ -34,7 +34,7 @@
 #' The branches that also used for missing values are marked as bold
 #' (as in "carrying extra capacity").
 #'
-#' This function uses \href{http://www.graphviz.org/}{GraphViz} as a backend of DiagrammeR.
+#' This function uses \href{https://www.graphviz.org/}{GraphViz} as a backend of DiagrammeR.
 #'
 #' @return
 #'
diff --git a/R-package/R/xgb.train.R b/R-package/R/xgb.train.R
index 580449791a62..f23700511684 100644
--- a/R-package/R/xgb.train.R
+++ b/R-package/R/xgb.train.R
@@ -192,8 +192,8 @@
 #' data(agaricus.train, package='xgboost')
 #' data(agaricus.test, package='xgboost')
 #'
-#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
-#' dtest <- with(agaricus.test, xgb.DMatrix(data, label = label))
+#' dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
+#' dtest <- with(agaricus.test, xgb.DMatrix(data, label = label, nthread = 2))
 #' watchlist <- list(train = dtrain, eval = dtest)
 #'
 #' ## A simple xgb.train example:
diff --git a/R-package/configure b/R-package/configure
index 154ed08fa047..258f86fd1f8a 100755
--- a/R-package/configure
+++ b/R-package/configure
@@ -1,9 +1,10 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for xgboost 1.7.0.
+# Generated by GNU Autoconf 2.71 for xgboost 1.7.5.
 #
 #
-# Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
+# Copyright (C) 1992-1996, 1998-2017, 2020-2021 Free Software Foundation,
+# Inc.
 #
 #
 # This configure script is free software; the Free Software Foundation
@@ -14,14 +15,16 @@
 
 # Be more Bourne compatible
 DUALCASE=1; export DUALCASE # for MKS sh
-if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+as_nop=:
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
   emulate sh
   NULLCMD=:
   # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
   # is contrary to our usage.  Disable this feature.
   alias -g '${1+"$@"}'='"$@"'
   setopt NO_GLOB_SUBST
-else
+else $as_nop
   case `(set -o) 2>/dev/null` in #(
   *posix*) :
     set -o posix ;; #(
@@ -31,46 +34,46 @@ esac
 fi
 
 
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
 as_nl='
 '
 export as_nl
-# Printing a long string crashes Solaris 7 /usr/bin/printf.
-as_echo='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
-as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo
-as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo$as_echo
-# Prefer a ksh shell builtin over an external printf program on Solaris,
-# but without wasting forks for bash or zsh.
-if test -z "$BASH_VERSION$ZSH_VERSION" \
-    && (test "X`print -r -- $as_echo`" = "X$as_echo") 2>/dev/null; then
-  as_echo='print -r --'
-  as_echo_n='print -rn --'
-elif (test "X`printf %s $as_echo`" = "X$as_echo") 2>/dev/null; then
-  as_echo='printf %s\n'
-  as_echo_n='printf %s'
-else
-  if test "X`(/usr/ucb/echo -n -n $as_echo) 2>/dev/null`" = "X-n $as_echo"; then
-    as_echo_body='eval /usr/ucb/echo -n "$1$as_nl"'
-    as_echo_n='/usr/ucb/echo -n'
-  else
-    as_echo_body='eval expr "X$1" : "X\\(.*\\)"'
-    as_echo_n_body='eval
-      arg=$1;
-      case $arg in #(
-      *"$as_nl"*)
-	expr "X$arg" : "X\\(.*\\)$as_nl";
-	arg=`expr "X$arg" : ".*$as_nl\\(.*\\)"`;;
-      esac;
-      expr "X$arg" : "X\\(.*\\)" | tr -d "$as_nl"
-    '
-    export as_echo_n_body
-    as_echo_n='sh -c $as_echo_n_body as_echo'
-  fi
-  export as_echo_body
-  as_echo='sh -c $as_echo_body as_echo'
-fi
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
 
 # The user is always right.
-if test "${PATH_SEPARATOR+set}" != set; then
+if ${PATH_SEPARATOR+false} :; then
   PATH_SEPARATOR=:
   (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
     (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
@@ -79,13 +82,6 @@ if test "${PATH_SEPARATOR+set}" != set; then
 fi
 
 
-# IFS
-# We need space, tab and new line, in precisely that order.  Quoting is
-# there to prevent editors from complaining about space-tab.
-# (If _AS_PATH_WALK were called with IFS unset, it would disable word
-# splitting by setting IFS to empty value.)
-IFS=" ""	$as_nl"
-
 # Find who we are.  Look in the path if we contain no directory separator.
 as_myself=
 case $0 in #((
@@ -94,8 +90,12 @@ case $0 in #((
 for as_dir in $PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    test -r "$as_dir/$0" && as_myself=$as_dir/$0 && break
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
   done
 IFS=$as_save_IFS
 
@@ -107,30 +107,10 @@ if test "x$as_myself" = x; then
   as_myself=$0
 fi
 if test ! -f "$as_myself"; then
-  $as_echo "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
   exit 1
 fi
 
-# Unset variables that we do not need and which cause bugs (e.g. in
-# pre-3.0 UWIN ksh).  But do not cause bugs in bash 2.01; the "|| exit 1"
-# suppresses any "Segmentation fault" message there.  '((' could
-# trigger a bug in pdksh 5.2.14.
-for as_var in BASH_ENV ENV MAIL MAILPATH
-do eval test x\${$as_var+set} = xset \
-  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
-done
-PS1='$ '
-PS2='> '
-PS4='+ '
-
-# NLS nuisances.
-LC_ALL=C
-export LC_ALL
-LANGUAGE=C
-export LANGUAGE
-
-# CDPATH.
-(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
 
 # Use a proper internal environment variable to ensure we don't fall
   # into an infinite loop, continuously re-executing ourselves.
@@ -152,20 +132,22 @@ esac
 exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
 # Admittedly, this is quite paranoid, since all the known shells bail
 # out after a failed `exec'.
-$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2
-as_fn_exit 255
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
   fi
   # We don't want this to propagate to other subprocesses.
           { _as_can_reexec=; unset _as_can_reexec;}
 if test "x$CONFIG_SHELL" = x; then
-  as_bourne_compatible="if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then :
+  as_bourne_compatible="as_nop=:
+if test \${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
   emulate sh
   NULLCMD=:
   # Pre-4.2 versions of Zsh do word splitting on \${1+\"\$@\"}, which
   # is contrary to our usage.  Disable this feature.
   alias -g '\${1+\"\$@\"}'='\"\$@\"'
   setopt NO_GLOB_SUBST
-else
+else \$as_nop
   case \`(set -o) 2>/dev/null\` in #(
   *posix*) :
     set -o posix ;; #(
@@ -185,41 +167,52 @@ as_fn_success || { exitcode=1; echo as_fn_success failed.; }
 as_fn_failure && { exitcode=1; echo as_fn_failure succeeded.; }
 as_fn_ret_success || { exitcode=1; echo as_fn_ret_success failed.; }
 as_fn_ret_failure && { exitcode=1; echo as_fn_ret_failure succeeded.; }
-if ( set x; as_fn_ret_success y && test x = \"\$1\" ); then :
+if ( set x; as_fn_ret_success y && test x = \"\$1\" )
+then :
 
-else
+else \$as_nop
   exitcode=1; echo positional parameters were not saved.
 fi
 test x\$exitcode = x0 || exit 1
+blah=\$(echo \$(echo blah))
+test x\"\$blah\" = xblah || exit 1
 test -x / || exit 1"
   as_suggested="  as_lineno_1=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_1a=\$LINENO
   as_lineno_2=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_2a=\$LINENO
   eval 'test \"x\$as_lineno_1'\$as_run'\" != \"x\$as_lineno_2'\$as_run'\" &&
   test \"x\`expr \$as_lineno_1'\$as_run' + 1\`\" = \"x\$as_lineno_2'\$as_run'\"' || exit 1"
-  if (eval "$as_required") 2>/dev/null; then :
+  if (eval "$as_required") 2>/dev/null
+then :
   as_have_required=yes
-else
+else $as_nop
   as_have_required=no
 fi
-  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null; then :
+  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null
+then :
 
-else
+else $as_nop
   as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
 as_found=false
 for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
   as_found=:
   case $as_dir in #(
 	 /*)
 	   for as_base in sh bash ksh sh5; do
 	     # Try only shells that exist, to save several forks.
-	     as_shell=$as_dir/$as_base
+	     as_shell=$as_dir$as_base
 	     if { test -f "$as_shell" || test -f "$as_shell.exe"; } &&
-		    { $as_echo "$as_bourne_compatible""$as_required" | as_run=a "$as_shell"; } 2>/dev/null; then :
+		    as_run=a "$as_shell" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
   CONFIG_SHELL=$as_shell as_have_required=yes
-		   if { $as_echo "$as_bourne_compatible""$as_suggested" | as_run=a "$as_shell"; } 2>/dev/null; then :
+		   if as_run=a "$as_shell" -c "$as_bourne_compatible""$as_suggested" 2>/dev/null
+then :
   break 2
 fi
 fi
@@ -227,14 +220,21 @@ fi
        esac
   as_found=false
 done
-$as_found || { if { test -f "$SHELL" || test -f "$SHELL.exe"; } &&
-	      { $as_echo "$as_bourne_compatible""$as_required" | as_run=a "$SHELL"; } 2>/dev/null; then :
-  CONFIG_SHELL=$SHELL as_have_required=yes
-fi; }
 IFS=$as_save_IFS
+if $as_found
+then :
 
+else $as_nop
+  if { test -f "$SHELL" || test -f "$SHELL.exe"; } &&
+	      as_run=a "$SHELL" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
+  CONFIG_SHELL=$SHELL as_have_required=yes
+fi
+fi
 
-      if test "x$CONFIG_SHELL" != x; then :
+
+      if test "x$CONFIG_SHELL" != x
+then :
   export CONFIG_SHELL
              # We cannot yet assume a decent shell, so we have to provide a
 # neutralization value for shells without unset; and this also
@@ -252,18 +252,19 @@ esac
 exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
 # Admittedly, this is quite paranoid, since all the known shells bail
 # out after a failed `exec'.
-$as_echo "$0: could not re-execute with $CONFIG_SHELL" >&2
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
 exit 255
 fi
 
-    if test x$as_have_required = xno; then :
-  $as_echo "$0: This script requires a shell more modern than all"
-  $as_echo "$0: the shells that I found on your system."
-  if test x${ZSH_VERSION+set} = xset ; then
-    $as_echo "$0: In particular, zsh $ZSH_VERSION has bugs and should"
-    $as_echo "$0: be upgraded to zsh 4.3.4 or later."
+    if test x$as_have_required = xno
+then :
+  printf "%s\n" "$0: This script requires a shell more modern than all"
+  printf "%s\n" "$0: the shells that I found on your system."
+  if test ${ZSH_VERSION+y} ; then
+    printf "%s\n" "$0: In particular, zsh $ZSH_VERSION has bugs and should"
+    printf "%s\n" "$0: be upgraded to zsh 4.3.4 or later."
   else
-    $as_echo "$0: Please tell bug-autoconf@gnu.org about your system,
+    printf "%s\n" "$0: Please tell bug-autoconf@gnu.org about your system,
 $0: including any error possibly output before this
 $0: message. Then install a modern shell, or manually run
 $0: the script under such a shell if you do have one."
@@ -290,6 +291,7 @@ as_fn_unset ()
 }
 as_unset=as_fn_unset
 
+
 # as_fn_set_status STATUS
 # -----------------------
 # Set $? to STATUS, without forking.
@@ -307,6 +309,14 @@ as_fn_exit ()
   as_fn_set_status $1
   exit $1
 } # as_fn_exit
+# as_fn_nop
+# ---------
+# Do nothing but, unlike ":", preserve the value of $?.
+as_fn_nop ()
+{
+  return $?
+}
+as_nop=as_fn_nop
 
 # as_fn_mkdir_p
 # -------------
@@ -321,7 +331,7 @@ as_fn_mkdir_p ()
     as_dirs=
     while :; do
       case $as_dir in #(
-      *\'*) as_qdir=`$as_echo "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
       *) as_qdir=$as_dir;;
       esac
       as_dirs="'$as_qdir' $as_dirs"
@@ -330,7 +340,7 @@ $as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
 	 X"$as_dir" : 'X\(//\)[^/]' \| \
 	 X"$as_dir" : 'X\(//\)$' \| \
 	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X"$as_dir" |
+printf "%s\n" X"$as_dir" |
     sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
 	    s//\1/
 	    q
@@ -369,12 +379,13 @@ as_fn_executable_p ()
 # advantage of any shell optimizations that allow amortized linear growth over
 # repeated appends, instead of the typical quadratic growth present in naive
 # implementations.
-if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null; then :
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
   eval 'as_fn_append ()
   {
     eval $1+=\$2
   }'
-else
+else $as_nop
   as_fn_append ()
   {
     eval $1=\$$1\$2
@@ -386,18 +397,27 @@ fi # as_fn_append
 # Perform arithmetic evaluation on the ARGs, and store the result in the
 # global $as_val. Take advantage of shells that can avoid forks. The arguments
 # must be portable across $(()) and expr.
-if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null; then :
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
   eval 'as_fn_arith ()
   {
     as_val=$(( $* ))
   }'
-else
+else $as_nop
   as_fn_arith ()
   {
     as_val=`expr "$@" || test $? -eq 1`
   }
 fi # as_fn_arith
 
+# as_fn_nop
+# ---------
+# Do nothing but, unlike ":", preserve the value of $?.
+as_fn_nop ()
+{
+  return $?
+}
+as_nop=as_fn_nop
 
 # as_fn_error STATUS ERROR [LINENO LOG_FD]
 # ----------------------------------------
@@ -409,9 +429,9 @@ as_fn_error ()
   as_status=$1; test $as_status -eq 0 && as_status=1
   if test "$4"; then
     as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
   fi
-  $as_echo "$as_me: error: $2" >&2
+  printf "%s\n" "$as_me: error: $2" >&2
   as_fn_exit $as_status
 } # as_fn_error
 
@@ -438,7 +458,7 @@ as_me=`$as_basename -- "$0" ||
 $as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
 	 X"$0" : 'X\(//\)$' \| \
 	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X/"$0" |
+printf "%s\n" X/"$0" |
     sed '/^.*\/\([^/][^/]*\)\/*$/{
 	    s//\1/
 	    q
@@ -482,7 +502,7 @@ as_cr_alnum=$as_cr_Letters$as_cr_digits
       s/-\n.*//
     ' >$as_me.lineno &&
   chmod +x "$as_me.lineno" ||
-    { $as_echo "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; }
+    { printf "%s\n" "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; }
 
   # If we had to re-execute with $CONFIG_SHELL, we're ensured to have
   # already done that, so ensure we don't try to do so again and fall
@@ -496,6 +516,10 @@ as_cr_alnum=$as_cr_Letters$as_cr_digits
   exit
 }
 
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
 ECHO_C= ECHO_N= ECHO_T=
 case `echo -n x` in #(((((
 -n*)
@@ -509,6 +533,13 @@ case `echo -n x` in #(((((
   ECHO_N='-n';;
 esac
 
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
+
 rm -f conf$$ conf$$.exe conf$$.file
 if test -d conf$$.dir; then
   rm -f conf$$.dir/conf$$.file
@@ -576,8 +607,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='xgboost'
 PACKAGE_TARNAME='xgboost'
-PACKAGE_VERSION='1.7.0'
-PACKAGE_STRING='xgboost 1.7.0'
+PACKAGE_VERSION='1.7.5'
+PACKAGE_STRING='xgboost 1.7.5'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''
 
@@ -589,11 +620,11 @@ OPENMP_LIB
 OPENMP_CXXFLAGS
 OBJEXT
 EXEEXT
-ac_ct_CC
+ac_ct_CXX
 CPPFLAGS
 LDFLAGS
-CFLAGS
-CC
+CXXFLAGS
+CXX
 target_alias
 host_alias
 build_alias
@@ -640,11 +671,12 @@ enable_option_checking
       ac_precious_vars='build_alias
 host_alias
 target_alias
-CC
-CFLAGS
+CXX
+CXXFLAGS
 LDFLAGS
 LIBS
-CPPFLAGS'
+CPPFLAGS
+CCC'
 
 
 # Initialize some variables set by options.
@@ -713,8 +745,6 @@ do
   *)    ac_optarg=yes ;;
   esac
 
-  # Accept the important Cygnus configure options, so we can diagnose typos.
-
   case $ac_dashdash$ac_option in
   --)
     ac_dashdash=yes ;;
@@ -755,9 +785,9 @@ do
     ac_useropt=`expr "x$ac_option" : 'x-*disable-\(.*\)'`
     # Reject names that are not valid shell variable names.
     expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
-      as_fn_error $? "invalid feature name: $ac_useropt"
+      as_fn_error $? "invalid feature name: \`$ac_useropt'"
     ac_useropt_orig=$ac_useropt
-    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
       *"
 "enable_$ac_useropt"
@@ -781,9 +811,9 @@ do
     ac_useropt=`expr "x$ac_option" : 'x-*enable-\([^=]*\)'`
     # Reject names that are not valid shell variable names.
     expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
-      as_fn_error $? "invalid feature name: $ac_useropt"
+      as_fn_error $? "invalid feature name: \`$ac_useropt'"
     ac_useropt_orig=$ac_useropt
-    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
       *"
 "enable_$ac_useropt"
@@ -994,9 +1024,9 @@ do
     ac_useropt=`expr "x$ac_option" : 'x-*with-\([^=]*\)'`
     # Reject names that are not valid shell variable names.
     expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
-      as_fn_error $? "invalid package name: $ac_useropt"
+      as_fn_error $? "invalid package name: \`$ac_useropt'"
     ac_useropt_orig=$ac_useropt
-    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
       *"
 "with_$ac_useropt"
@@ -1010,9 +1040,9 @@ do
     ac_useropt=`expr "x$ac_option" : 'x-*without-\(.*\)'`
     # Reject names that are not valid shell variable names.
     expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
-      as_fn_error $? "invalid package name: $ac_useropt"
+      as_fn_error $? "invalid package name: \`$ac_useropt'"
     ac_useropt_orig=$ac_useropt
-    ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
       *"
 "with_$ac_useropt"
@@ -1056,9 +1086,9 @@ Try \`$0 --help' for more information"
 
   *)
     # FIXME: should be removed in autoconf 3.0.
-    $as_echo "$as_me: WARNING: you should use --build, --host, --target" >&2
+    printf "%s\n" "$as_me: WARNING: you should use --build, --host, --target" >&2
     expr "x$ac_option" : ".*[^-._$as_cr_alnum]" >/dev/null &&
-      $as_echo "$as_me: WARNING: invalid host type: $ac_option" >&2
+      printf "%s\n" "$as_me: WARNING: invalid host type: $ac_option" >&2
     : "${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}"
     ;;
 
@@ -1074,7 +1104,7 @@ if test -n "$ac_unrecognized_opts"; then
   case $enable_option_checking in
     no) ;;
     fatal) as_fn_error $? "unrecognized options: $ac_unrecognized_opts" ;;
-    *)     $as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
+    *)     printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
   esac
 fi
 
@@ -1138,7 +1168,7 @@ $as_expr X"$as_myself" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
 	 X"$as_myself" : 'X\(//\)[^/]' \| \
 	 X"$as_myself" : 'X\(//\)$' \| \
 	 X"$as_myself" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X"$as_myself" |
+printf "%s\n" X"$as_myself" |
     sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
 	    s//\1/
 	    q
@@ -1195,7 +1225,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures xgboost 1.7.0 to adapt to many kinds of systems.
+\`configure' configures xgboost 1.7.5 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1257,13 +1287,13 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of xgboost 1.7.0:";;
+     short | recursive ) echo "Configuration of xgboost 1.7.5:";;
    esac
   cat <<\_ACEOF
 
 Some influential environment variables:
-  CC          C compiler command
-  CFLAGS      C compiler flags
+  CXX         C++ compiler command
+  CXXFLAGS    C++ compiler flags
   LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
               nonstandard directory <lib dir>
   LIBS        libraries to pass to the linker, e.g. -l<library>
@@ -1289,9 +1319,9 @@ if test "$ac_init_help" = "recursive"; then
 case "$ac_dir" in
 .) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
 *)
-  ac_dir_suffix=/`$as_echo "$ac_dir" | sed 's|^\.[\\/]||'`
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
   # A ".." for each directory in $ac_dir_suffix.
-  ac_top_builddir_sub=`$as_echo "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
   case $ac_top_builddir_sub in
   "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
   *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
@@ -1319,7 +1349,8 @@ esac
 ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
 
     cd "$ac_dir" || { ac_status=$?; continue; }
-    # Check for guested configure.
+    # Check for configure.gnu first; this name is used for a wrapper for
+    # Metaconfig's "Configure" on case-insensitive file systems.
     if test -f "$ac_srcdir/configure.gnu"; then
       echo &&
       $SHELL "$ac_srcdir/configure.gnu" --help=recursive
@@ -1327,7 +1358,7 @@ ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
       echo &&
       $SHELL "$ac_srcdir/configure" --help=recursive
     else
-      $as_echo "$as_me: WARNING: no configuration information is in $ac_dir" >&2
+      printf "%s\n" "$as_me: WARNING: no configuration information is in $ac_dir" >&2
     fi || ac_status=$?
     cd "$ac_pwd" || { ac_status=$?; break; }
   done
@@ -1336,10 +1367,10 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-xgboost configure 1.7.0
-generated by GNU Autoconf 2.69
+xgboost configure 1.7.5
+generated by GNU Autoconf 2.71
 
-Copyright (C) 2012 Free Software Foundation, Inc.
+Copyright (C) 2021 Free Software Foundation, Inc.
 This configure script is free software; the Free Software Foundation
 gives unlimited permission to copy, distribute and modify it.
 _ACEOF
@@ -1350,20 +1381,20 @@ fi
 ## Autoconf initialization. ##
 ## ------------------------ ##
 
-# ac_fn_c_try_compile LINENO
-# --------------------------
+# ac_fn_cxx_try_compile LINENO
+# ----------------------------
 # Try to compile conftest.$ac_ext, and return whether this succeeded.
-ac_fn_c_try_compile ()
+ac_fn_cxx_try_compile ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  rm -f conftest.$ac_objext
+  rm -f conftest.$ac_objext conftest.beam
   if { { ac_try="$ac_compile"
 case "(($ac_try" in
   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_compile") 2>conftest.err
   ac_status=$?
   if test -s conftest.err; then
@@ -1371,14 +1402,15 @@ $as_echo "$ac_try_echo"; } >&5
     cat conftest.er1 >&5
     mv -f conftest.er1 conftest.err
   fi
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; } && {
-	 test -z "$ac_c_werror_flag" ||
+	 test -z "$ac_cxx_werror_flag" ||
 	 test ! -s conftest.err
-       } && test -s conftest.$ac_objext; then :
+       } && test -s conftest.$ac_objext
+then :
   ac_retval=0
-else
-  $as_echo "$as_me: failed program was:" >&5
+else $as_nop
+  printf "%s\n" "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
 	ac_retval=1
@@ -1386,22 +1418,22 @@ fi
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
-} # ac_fn_c_try_compile
+} # ac_fn_cxx_try_compile
 
-# ac_fn_c_try_link LINENO
-# -----------------------
+# ac_fn_cxx_try_link LINENO
+# -------------------------
 # Try to link conftest.$ac_ext, and return whether this succeeded.
-ac_fn_c_try_link ()
+ac_fn_cxx_try_link ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  rm -f conftest.$ac_objext conftest$ac_exeext
+  rm -f conftest.$ac_objext conftest.beam conftest$ac_exeext
   if { { ac_try="$ac_link"
 case "(($ac_try" in
   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_link") 2>conftest.err
   ac_status=$?
   if test -s conftest.err; then
@@ -1409,17 +1441,18 @@ $as_echo "$ac_try_echo"; } >&5
     cat conftest.er1 >&5
     mv -f conftest.er1 conftest.err
   fi
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; } && {
-	 test -z "$ac_c_werror_flag" ||
+	 test -z "$ac_cxx_werror_flag" ||
 	 test ! -s conftest.err
        } && test -s conftest$ac_exeext && {
 	 test "$cross_compiling" = yes ||
 	 test -x conftest$ac_exeext
-       }; then :
+       }
+then :
   ac_retval=0
-else
-  $as_echo "$as_me: failed program was:" >&5
+else $as_nop
+  printf "%s\n" "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
 	ac_retval=1
@@ -1432,13 +1465,13 @@ fi
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
-} # ac_fn_c_try_link
+} # ac_fn_cxx_try_link
 
-# ac_fn_c_try_run LINENO
-# ----------------------
-# Try to link conftest.$ac_ext, and return whether this succeeded. Assumes
-# that executables *can* be run.
-ac_fn_c_try_run ()
+# ac_fn_cxx_try_run LINENO
+# ------------------------
+# Try to run conftest.$ac_ext, and return whether this succeeded. Assumes that
+# executables *can* be run.
+ac_fn_cxx_try_run ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
   if { { ac_try="$ac_link"
@@ -1447,25 +1480,26 @@ case "(($ac_try" in
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_link") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; } && { ac_try='./conftest$ac_exeext'
   { { case "(($ac_try" in
   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_try") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then :
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
   ac_retval=0
-else
-  $as_echo "$as_me: program exited with status $ac_status" >&5
-       $as_echo "$as_me: failed program was:" >&5
+else $as_nop
+  printf "%s\n" "$as_me: program exited with status $ac_status" >&5
+       printf "%s\n" "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
        ac_retval=$ac_status
@@ -1474,15 +1508,35 @@ fi
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
-} # ac_fn_c_try_run
+} # ac_fn_cxx_try_run
+ac_configure_args_raw=
+for ac_arg
+do
+  case $ac_arg in
+  *\'*)
+    ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+  esac
+  as_fn_append ac_configure_args_raw " '$ac_arg'"
+done
+
+case $ac_configure_args_raw in
+  *$as_nl*)
+    ac_safe_unquote= ;;
+  *)
+    ac_unsafe_z='|&;<>()$`\\"*?[ ''	' # This string ends in space, tab.
+    ac_unsafe_a="$ac_unsafe_z#~"
+    ac_safe_unquote="s/ '\\([^$ac_unsafe_a][^$ac_unsafe_z]*\\)'/ \\1/g"
+    ac_configure_args_raw=`      printf "%s\n" "$ac_configure_args_raw" | sed "$ac_safe_unquote"`;;
+esac
+
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by xgboost $as_me 1.7.0, which was
-generated by GNU Autoconf 2.69.  Invocation command line was
+It was created by xgboost $as_me 1.7.5, which was
+generated by GNU Autoconf 2.71.  Invocation command line was
 
-  $ $0 $@
+  $ $0$ac_configure_args_raw
 
 _ACEOF
 exec 5>>config.log
@@ -1515,8 +1569,12 @@ as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
 for as_dir in $PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    $as_echo "PATH: $as_dir"
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    printf "%s\n" "PATH: $as_dir"
   done
 IFS=$as_save_IFS
 
@@ -1551,7 +1609,7 @@ do
     | -silent | --silent | --silen | --sile | --sil)
       continue ;;
     *\'*)
-      ac_arg=`$as_echo "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+      ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
     esac
     case $ac_pass in
     1) as_fn_append ac_configure_args0 " '$ac_arg'" ;;
@@ -1586,11 +1644,13 @@ done
 # WARNING: Use '\'' to represent an apostrophe within the trap.
 # WARNING: Do not start the trap code with a newline, due to a FreeBSD 4.0 bug.
 trap 'exit_status=$?
+  # Sanitize IFS.
+  IFS=" ""	$as_nl"
   # Save into config.log some information that might help in debugging.
   {
     echo
 
-    $as_echo "## ---------------- ##
+    printf "%s\n" "## ---------------- ##
 ## Cache variables. ##
 ## ---------------- ##"
     echo
@@ -1601,8 +1661,8 @@ trap 'exit_status=$?
     case $ac_val in #(
     *${as_nl}*)
       case $ac_var in #(
-      *_cv_*) { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
-$as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
       esac
       case $ac_var in #(
       _ | IFS | as_nl) ;; #(
@@ -1626,7 +1686,7 @@ $as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
 )
     echo
 
-    $as_echo "## ----------------- ##
+    printf "%s\n" "## ----------------- ##
 ## Output variables. ##
 ## ----------------- ##"
     echo
@@ -1634,14 +1694,14 @@ $as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
     do
       eval ac_val=\$$ac_var
       case $ac_val in
-      *\'\''*) ac_val=`$as_echo "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+      *\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
       esac
-      $as_echo "$ac_var='\''$ac_val'\''"
+      printf "%s\n" "$ac_var='\''$ac_val'\''"
     done | sort
     echo
 
     if test -n "$ac_subst_files"; then
-      $as_echo "## ------------------- ##
+      printf "%s\n" "## ------------------- ##
 ## File substitutions. ##
 ## ------------------- ##"
       echo
@@ -1649,15 +1709,15 @@ $as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
       do
 	eval ac_val=\$$ac_var
 	case $ac_val in
-	*\'\''*) ac_val=`$as_echo "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+	*\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
 	esac
-	$as_echo "$ac_var='\''$ac_val'\''"
+	printf "%s\n" "$ac_var='\''$ac_val'\''"
       done | sort
       echo
     fi
 
     if test -s confdefs.h; then
-      $as_echo "## ----------- ##
+      printf "%s\n" "## ----------- ##
 ## confdefs.h. ##
 ## ----------- ##"
       echo
@@ -1665,8 +1725,8 @@ $as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
       echo
     fi
     test "$ac_signal" != 0 &&
-      $as_echo "$as_me: caught signal $ac_signal"
-    $as_echo "$as_me: exit $exit_status"
+      printf "%s\n" "$as_me: caught signal $ac_signal"
+    printf "%s\n" "$as_me: exit $exit_status"
   } >&5
   rm -f core *.core core.conftest.* &&
     rm -f -r conftest* confdefs* conf$$* $ac_clean_files &&
@@ -1680,63 +1740,48 @@ ac_signal=0
 # confdefs.h avoids OS command line length limits that DEFS can exceed.
 rm -f -r conftest* confdefs.h
 
-$as_echo "/* confdefs.h */" > confdefs.h
+printf "%s\n" "/* confdefs.h */" > confdefs.h
 
 # Predefined preprocessor variables.
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_NAME "$PACKAGE_NAME"
-_ACEOF
+printf "%s\n" "#define PACKAGE_NAME \"$PACKAGE_NAME\"" >>confdefs.h
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_TARNAME "$PACKAGE_TARNAME"
-_ACEOF
+printf "%s\n" "#define PACKAGE_TARNAME \"$PACKAGE_TARNAME\"" >>confdefs.h
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_VERSION "$PACKAGE_VERSION"
-_ACEOF
+printf "%s\n" "#define PACKAGE_VERSION \"$PACKAGE_VERSION\"" >>confdefs.h
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_STRING "$PACKAGE_STRING"
-_ACEOF
+printf "%s\n" "#define PACKAGE_STRING \"$PACKAGE_STRING\"" >>confdefs.h
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_BUGREPORT "$PACKAGE_BUGREPORT"
-_ACEOF
+printf "%s\n" "#define PACKAGE_BUGREPORT \"$PACKAGE_BUGREPORT\"" >>confdefs.h
 
-cat >>confdefs.h <<_ACEOF
-#define PACKAGE_URL "$PACKAGE_URL"
-_ACEOF
+printf "%s\n" "#define PACKAGE_URL \"$PACKAGE_URL\"" >>confdefs.h
 
 
 # Let the site file select an alternate cache file if it wants to.
 # Prefer an explicitly selected file to automatically selected ones.
-ac_site_file1=NONE
-ac_site_file2=NONE
 if test -n "$CONFIG_SITE"; then
-  # We do not want a PATH search for config.site.
-  case $CONFIG_SITE in #((
-    -*)  ac_site_file1=./$CONFIG_SITE;;
-    */*) ac_site_file1=$CONFIG_SITE;;
-    *)   ac_site_file1=./$CONFIG_SITE;;
-  esac
+  ac_site_files="$CONFIG_SITE"
 elif test "x$prefix" != xNONE; then
-  ac_site_file1=$prefix/share/config.site
-  ac_site_file2=$prefix/etc/config.site
+  ac_site_files="$prefix/share/config.site $prefix/etc/config.site"
 else
-  ac_site_file1=$ac_default_prefix/share/config.site
-  ac_site_file2=$ac_default_prefix/etc/config.site
+  ac_site_files="$ac_default_prefix/share/config.site $ac_default_prefix/etc/config.site"
 fi
-for ac_site_file in "$ac_site_file1" "$ac_site_file2"
+
+for ac_site_file in $ac_site_files
 do
-  test "x$ac_site_file" = xNONE && continue
-  if test /dev/null != "$ac_site_file" && test -r "$ac_site_file"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
-$as_echo "$as_me: loading site script $ac_site_file" >&6;}
+  case $ac_site_file in #(
+  */*) :
+     ;; #(
+  *) :
+    ac_site_file=./$ac_site_file ;;
+esac
+  if test -f "$ac_site_file" && test -r "$ac_site_file"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
+printf "%s\n" "$as_me: loading site script $ac_site_file" >&6;}
     sed 's/^/| /' "$ac_site_file" >&5
     . "$ac_site_file" \
-      || { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+      || { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "failed to load site script $ac_site_file
 See \`config.log' for more details" "$LINENO" 5; }
   fi
@@ -1746,19 +1791,235 @@ if test -r "$cache_file"; then
   # Some versions of bash will fail to source /dev/null (special files
   # actually), so we avoid doing that.  DJGPP emulates it as a regular file.
   if test /dev/null != "$cache_file" && test -f "$cache_file"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: loading cache $cache_file" >&5
-$as_echo "$as_me: loading cache $cache_file" >&6;}
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading cache $cache_file" >&5
+printf "%s\n" "$as_me: loading cache $cache_file" >&6;}
     case $cache_file in
       [\\/]* | ?:[\\/]* ) . "$cache_file";;
       *)                      . "./$cache_file";;
     esac
   fi
 else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: creating cache $cache_file" >&5
-$as_echo "$as_me: creating cache $cache_file" >&6;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating cache $cache_file" >&5
+printf "%s\n" "$as_me: creating cache $cache_file" >&6;}
   >$cache_file
 fi
 
+# Test code for whether the C++ compiler supports C++98 (global declarations)
+ac_cxx_conftest_cxx98_globals='
+// Does the compiler advertise C++98 conformance?
+#if !defined __cplusplus || __cplusplus < 199711L
+# error "Compiler does not advertise C++98 conformance"
+#endif
+
+// These inclusions are to reject old compilers that
+// lack the unsuffixed header files.
+#include <cstdlib>
+#include <exception>
+
+// <cassert> and <cstring> are *not* freestanding headers in C++98.
+extern void assert (int);
+namespace std {
+  extern int strcmp (const char *, const char *);
+}
+
+// Namespaces, exceptions, and templates were all added after "C++ 2.0".
+using std::exception;
+using std::strcmp;
+
+namespace {
+
+void test_exception_syntax()
+{
+  try {
+    throw "test";
+  } catch (const char *s) {
+    // Extra parentheses suppress a warning when building autoconf itself,
+    // due to lint rules shared with more typical C programs.
+    assert (!(strcmp) (s, "test"));
+  }
+}
+
+template <typename T> struct test_template
+{
+  T const val;
+  explicit test_template(T t) : val(t) {}
+  template <typename U> T add(U u) { return static_cast<T>(u) + val; }
+};
+
+} // anonymous namespace
+'
+
+# Test code for whether the C++ compiler supports C++98 (body of main)
+ac_cxx_conftest_cxx98_main='
+  assert (argc);
+  assert (! argv[0]);
+{
+  test_exception_syntax ();
+  test_template<double> tt (2.0);
+  assert (tt.add (4) == 6.0);
+  assert (true && !false);
+}
+'
+
+# Test code for whether the C++ compiler supports C++11 (global declarations)
+ac_cxx_conftest_cxx11_globals='
+// Does the compiler advertise C++ 2011 conformance?
+#if !defined __cplusplus || __cplusplus < 201103L
+# error "Compiler does not advertise C++11 conformance"
+#endif
+
+namespace cxx11test
+{
+  constexpr int get_val() { return 20; }
+
+  struct testinit
+  {
+    int i;
+    double d;
+  };
+
+  class delegate
+  {
+  public:
+    delegate(int n) : n(n) {}
+    delegate(): delegate(2354) {}
+
+    virtual int getval() { return this->n; };
+  protected:
+    int n;
+  };
+
+  class overridden : public delegate
+  {
+  public:
+    overridden(int n): delegate(n) {}
+    virtual int getval() override final { return this->n * 2; }
+  };
+
+  class nocopy
+  {
+  public:
+    nocopy(int i): i(i) {}
+    nocopy() = default;
+    nocopy(const nocopy&) = delete;
+    nocopy & operator=(const nocopy&) = delete;
+  private:
+    int i;
+  };
+
+  // for testing lambda expressions
+  template <typename Ret, typename Fn> Ret eval(Fn f, Ret v)
+  {
+    return f(v);
+  }
+
+  // for testing variadic templates and trailing return types
+  template <typename V> auto sum(V first) -> V
+  {
+    return first;
+  }
+  template <typename V, typename... Args> auto sum(V first, Args... rest) -> V
+  {
+    return first + sum(rest...);
+  }
+}
+'
+
+# Test code for whether the C++ compiler supports C++11 (body of main)
+ac_cxx_conftest_cxx11_main='
+{
+  // Test auto and decltype
+  auto a1 = 6538;
+  auto a2 = 48573953.4;
+  auto a3 = "String literal";
+
+  int total = 0;
+  for (auto i = a3; *i; ++i) { total += *i; }
+
+  decltype(a2) a4 = 34895.034;
+}
+{
+  // Test constexpr
+  short sa[cxx11test::get_val()] = { 0 };
+}
+{
+  // Test initializer lists
+  cxx11test::testinit il = { 4323, 435234.23544 };
+}
+{
+  // Test range-based for
+  int array[] = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3,
+                 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+  for (auto &x : array) { x += 23; }
+}
+{
+  // Test lambda expressions
+  using cxx11test::eval;
+  assert (eval ([](int x) { return x*2; }, 21) == 42);
+  double d = 2.0;
+  assert (eval ([&](double x) { return d += x; }, 3.0) == 5.0);
+  assert (d == 5.0);
+  assert (eval ([=](double x) mutable { return d += x; }, 4.0) == 9.0);
+  assert (d == 5.0);
+}
+{
+  // Test use of variadic templates
+  using cxx11test::sum;
+  auto a = sum(1);
+  auto b = sum(1, 2);
+  auto c = sum(1.0, 2.0, 3.0);
+}
+{
+  // Test constructor delegation
+  cxx11test::delegate d1;
+  cxx11test::delegate d2();
+  cxx11test::delegate d3(45);
+}
+{
+  // Test override and final
+  cxx11test::overridden o1(55464);
+}
+{
+  // Test nullptr
+  char *c = nullptr;
+}
+{
+  // Test template brackets
+  test_template<::test_template<int>> v(test_template<int>(12));
+}
+{
+  // Unicode literals
+  char const *utf8 = u8"UTF-8 string \u2500";
+  char16_t const *utf16 = u"UTF-8 string \u2500";
+  char32_t const *utf32 = U"UTF-32 string \u2500";
+}
+'
+
+# Test code for whether the C compiler supports C++11 (complete).
+ac_cxx_conftest_cxx11_program="${ac_cxx_conftest_cxx98_globals}
+${ac_cxx_conftest_cxx11_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_cxx_conftest_cxx98_main}
+  ${ac_cxx_conftest_cxx11_main}
+  return ok;
+}
+"
+
+# Test code for whether the C compiler supports C++98 (complete).
+ac_cxx_conftest_cxx98_program="${ac_cxx_conftest_cxx98_globals}
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_cxx_conftest_cxx98_main}
+  return ok;
+}
+"
+
 # Check that the precious variables saved in the cache have kept the same
 # value.
 ac_cache_corrupted=false
@@ -1769,12 +2030,12 @@ for ac_var in $ac_precious_vars; do
   eval ac_new_val=\$ac_env_${ac_var}_value
   case $ac_old_set,$ac_new_set in
     set,)
-      { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&5
-$as_echo "$as_me: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&2;}
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&2;}
       ac_cache_corrupted=: ;;
     ,set)
-      { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was not set in the previous run" >&5
-$as_echo "$as_me: error: \`$ac_var' was not set in the previous run" >&2;}
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was not set in the previous run" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' was not set in the previous run" >&2;}
       ac_cache_corrupted=: ;;
     ,);;
     *)
@@ -1783,24 +2044,24 @@ $as_echo "$as_me: error: \`$ac_var' was not set in the previous run" >&2;}
 	ac_old_val_w=`echo x $ac_old_val`
 	ac_new_val_w=`echo x $ac_new_val`
 	if test "$ac_old_val_w" != "$ac_new_val_w"; then
-	  { $as_echo "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' has changed since the previous run:" >&5
-$as_echo "$as_me: error: \`$ac_var' has changed since the previous run:" >&2;}
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' has changed since the previous run:" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' has changed since the previous run:" >&2;}
 	  ac_cache_corrupted=:
 	else
-	  { $as_echo "$as_me:${as_lineno-$LINENO}: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&5
-$as_echo "$as_me: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&2;}
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&5
+printf "%s\n" "$as_me: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&2;}
 	  eval $ac_var=\$ac_old_val
 	fi
-	{ $as_echo "$as_me:${as_lineno-$LINENO}:   former value:  \`$ac_old_val'" >&5
-$as_echo "$as_me:   former value:  \`$ac_old_val'" >&2;}
-	{ $as_echo "$as_me:${as_lineno-$LINENO}:   current value: \`$ac_new_val'" >&5
-$as_echo "$as_me:   current value: \`$ac_new_val'" >&2;}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   former value:  \`$ac_old_val'" >&5
+printf "%s\n" "$as_me:   former value:  \`$ac_old_val'" >&2;}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   current value: \`$ac_new_val'" >&5
+printf "%s\n" "$as_me:   current value: \`$ac_new_val'" >&2;}
       fi;;
   esac
   # Pass precious variables to config.status.
   if test "$ac_new_set" = set; then
     case $ac_new_val in
-    *\'*) ac_arg=$ac_var=`$as_echo "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
+    *\'*) ac_arg=$ac_var=`printf "%s\n" "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
     *) ac_arg=$ac_var=$ac_new_val ;;
     esac
     case " $ac_configure_args " in
@@ -1810,11 +2071,12 @@ $as_echo "$as_me:   current value: \`$ac_new_val'" >&2;}
   fi
 done
 if $ac_cache_corrupted; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-  { $as_echo "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
-$as_echo "$as_me: error: changes in the environment can compromise the build" >&2;}
-  as_fn_error $? "run \`make distclean' and/or \`rm $cache_file' and start over" "$LINENO" 5
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
+printf "%s\n" "$as_me: error: changes in the environment can compromise the build" >&2;}
+  as_fn_error $? "run \`${MAKE-make} distclean' and/or \`rm $cache_file'
+	    and start over" "$LINENO" 5
 fi
 ## -------------------- ##
 ## Main body of script. ##
@@ -1828,224 +2090,76 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-# Use this line to set CC variable to a C compiler
-ac_ext=c
-ac_cpp='$CPP $CPPFLAGS'
-ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_c_compiler_gnu
-if test -n "$ac_tool_prefix"; then
-  # Extract the first word of "${ac_tool_prefix}gcc", so it can be a program name with args.
-set dummy ${ac_tool_prefix}gcc; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$CC"; then
-  ac_cv_prog_CC="$CC" # Let the user override the test.
-else
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_CC="${ac_tool_prefix}gcc"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
-
-fi
-fi
-CC=$ac_cv_prog_CC
-if test -n "$CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
-$as_echo "$CC" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
+: ${R_HOME=`R RHOME`}
+if test -z "${R_HOME}"; then
+  echo "could not determine R_HOME"
+  exit 1
 fi
 
+CXX17=`"${R_HOME}/bin/R" CMD config CXX17`
+CXX17STD=`"${R_HOME}/bin/R" CMD config CXX17STD`
+CXX="${CXX17} ${CXX17STD}"
+CXXFLAGS=`"${R_HOME}/bin/R" CMD config CXXFLAGS`
 
-fi
-if test -z "$ac_cv_prog_CC"; then
-  ac_ct_CC=$CC
-  # Extract the first word of "gcc", so it can be a program name with args.
-set dummy gcc; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_ac_ct_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$ac_ct_CC"; then
-  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
-else
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_ac_ct_CC="gcc"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
+CC=`"${R_HOME}/bin/R" CMD config CC`
+CFLAGS=`"${R_HOME}/bin/R" CMD config CFLAGS`
+CPPFLAGS=`"${R_HOME}/bin/R" CMD config CPPFLAGS`
 
-fi
-fi
-ac_ct_CC=$ac_cv_prog_ac_ct_CC
-if test -n "$ac_ct_CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
-$as_echo "$ac_ct_CC" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
+LDFLAGS=`"${R_HOME}/bin/R" CMD config LDFLAGS`
+ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
-  if test "x$ac_ct_CC" = x; then
-    CC=""
-  else
-    case $cross_compiling:$ac_tool_warned in
-yes:)
-{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
-$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
-ac_tool_warned=yes ;;
-esac
-    CC=$ac_ct_CC
-  fi
-else
-  CC="$ac_cv_prog_CC"
-fi
 
-if test -z "$CC"; then
-          if test -n "$ac_tool_prefix"; then
-    # Extract the first word of "${ac_tool_prefix}cc", so it can be a program name with args.
-set dummy ${ac_tool_prefix}cc; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$CC"; then
-  ac_cv_prog_CC="$CC" # Let the user override the test.
-else
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_CC="${ac_tool_prefix}cc"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
+### Check whether backtrace() is part of libc or the external lib libexecinfo
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking Backtrace lib" >&5
+printf %s "checking Backtrace lib... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: " >&5
+printf "%s\n" "" >&6; }
 
-fi
-fi
-CC=$ac_cv_prog_CC
-if test -n "$CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
-$as_echo "$CC" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
 
 
-  fi
-fi
-if test -z "$CC"; then
-  # Extract the first word of "cc", so it can be a program name with args.
-set dummy cc; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$CC"; then
-  ac_cv_prog_CC="$CC" # Let the user override the test.
-else
-  ac_prog_rejected=no
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    if test "$as_dir/$ac_word$ac_exec_ext" = "/usr/ucb/cc"; then
-       ac_prog_rejected=yes
-       continue
-     fi
-    ac_cv_prog_CC="cc"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
 
-if test $ac_prog_rejected = yes; then
-  # We found a bogon in the path, so make sure we never use it.
-  set dummy $ac_cv_prog_CC
-  shift
-  if test $# != 0; then
-    # We chose a different compiler from the bogus one.
-    # However, it has the same basename, so the bogon will be chosen
-    # first if we set CC to just the basename; use the full file name.
-    shift
-    ac_cv_prog_CC="$as_dir/$ac_word${1+' '}$@"
-  fi
-fi
-fi
-fi
-CC=$ac_cv_prog_CC
-if test -n "$CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
-$as_echo "$CC" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
 
 
-fi
-if test -z "$CC"; then
-  if test -n "$ac_tool_prefix"; then
-  for ac_prog in cl.exe
+ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+if test -z "$CXX"; then
+  if test -n "$CCC"; then
+    CXX=$CCC
+  else
+    if test -n "$ac_tool_prefix"; then
+  for ac_prog in g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC clang++
   do
     # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
 set dummy $ac_tool_prefix$ac_prog; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$CC"; then
-  ac_cv_prog_CC="$CC" # Let the user override the test.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CXX+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CXX"; then
+  ac_cv_prog_CXX="$CXX" # Let the user override the test.
 else
 as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
 for as_dir in $PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
     for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_CC="$ac_tool_prefix$ac_prog"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CXX="$ac_tool_prefix$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
     break 2
   fi
 done
@@ -2054,42 +2168,47 @@ IFS=$as_save_IFS
 
 fi
 fi
-CC=$ac_cv_prog_CC
-if test -n "$CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
-$as_echo "$CC" >&6; }
+CXX=$ac_cv_prog_CXX
+if test -n "$CXX"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CXX" >&5
+printf "%s\n" "$CXX" >&6; }
 else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
 fi
 
 
-    test -n "$CC" && break
+    test -n "$CXX" && break
   done
 fi
-if test -z "$CC"; then
-  ac_ct_CC=$CC
-  for ac_prog in cl.exe
+if test -z "$CXX"; then
+  ac_ct_CXX=$CXX
+  for ac_prog in g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC clang++
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_ac_ct_CC+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$ac_ct_CC"; then
-  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CXX+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$ac_ct_CXX"; then
+  ac_cv_prog_ac_ct_CXX="$ac_ct_CXX" # Let the user override the test.
 else
 as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
 for as_dir in $PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
     for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_ac_ct_CC="$ac_prog"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CXX="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
     break 2
   fi
 done
@@ -2098,42 +2217,36 @@ IFS=$as_save_IFS
 
 fi
 fi
-ac_ct_CC=$ac_cv_prog_ac_ct_CC
-if test -n "$ac_ct_CC"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
-$as_echo "$ac_ct_CC" >&6; }
+ac_ct_CXX=$ac_cv_prog_ac_ct_CXX
+if test -n "$ac_ct_CXX"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CXX" >&5
+printf "%s\n" "$ac_ct_CXX" >&6; }
 else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
 fi
 
 
-  test -n "$ac_ct_CC" && break
+  test -n "$ac_ct_CXX" && break
 done
 
-  if test "x$ac_ct_CC" = x; then
-    CC=""
+  if test "x$ac_ct_CXX" = x; then
+    CXX="g++"
   else
     case $cross_compiling:$ac_tool_warned in
 yes:)
-{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
-$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
 ac_tool_warned=yes ;;
 esac
-    CC=$ac_ct_CC
+    CXX=$ac_ct_CXX
   fi
 fi
 
+  fi
 fi
-
-
-test -z "$CC" && { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error $? "no acceptable C compiler found in \$PATH
-See \`config.log' for more details" "$LINENO" 5; }
-
 # Provide some information about the compiler.
-$as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
+printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C++ compiler version" >&5
 set X $ac_compile
 ac_compiler=$2
 for ac_option in --version -v -V -qversion; do
@@ -2143,7 +2256,7 @@ case "(($ac_try" in
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_compiler $ac_option >&5") 2>conftest.err
   ac_status=$?
   if test -s conftest.err; then
@@ -2153,7 +2266,7 @@ $as_echo "$ac_try_echo"; } >&5
     cat conftest.er1 >&5
   fi
   rm -f conftest.er1 conftest.err
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }
 done
 
@@ -2161,7 +2274,7 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 
   ;
@@ -2173,9 +2286,9 @@ ac_clean_files="$ac_clean_files a.out a.out.dSYM a.exe b.out"
 # Try to create an executable without -o first, disregard a.out.
 # It will help us diagnose broken compilers, and finding out an intuition
 # of exeext.
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the C compiler works" >&5
-$as_echo_n "checking whether the C compiler works... " >&6; }
-ac_link_default=`$as_echo "$ac_link" | sed 's/ -o *conftest[^ ]*//'`
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the C++ compiler works" >&5
+printf %s "checking whether the C++ compiler works... " >&6; }
+ac_link_default=`printf "%s\n" "$ac_link" | sed 's/ -o *conftest[^ ]*//'`
 
 # The possible output files:
 ac_files="a.out conftest.exe conftest a.exe a_out.exe b.out conftest.*"
@@ -2196,11 +2309,12 @@ case "(($ac_try" in
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_link_default") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; then :
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
   # Autoconf-2.13 could set the ac_cv_exeext variable to `no'.
 # So ignore a value of `no', otherwise this would lead to `EXEEXT = no'
 # in a Makefile.  We should not override ac_cv_exeext if it was cached,
@@ -2217,7 +2331,7 @@ do
 	# certainly right.
 	break;;
     *.* )
-	if test "${ac_cv_exeext+set}" = set && test "$ac_cv_exeext" != no;
+	if test ${ac_cv_exeext+y} && test "$ac_cv_exeext" != no;
 	then :; else
 	   ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
 	fi
@@ -2233,44 +2347,46 @@ do
 done
 test "$ac_cv_exeext" = no && ac_cv_exeext=
 
-else
+else $as_nop
   ac_file=''
 fi
-if test -z "$ac_file"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-$as_echo "$as_me: failed program was:" >&5
+if test -z "$ac_file"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+printf "%s\n" "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error 77 "C compiler cannot create executables
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "C++ compiler cannot create executables
 See \`config.log' for more details" "$LINENO" 5; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler default output file name" >&5
-$as_echo_n "checking for C compiler default output file name... " >&6; }
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_file" >&5
-$as_echo "$ac_file" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C++ compiler default output file name" >&5
+printf %s "checking for C++ compiler default output file name... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_file" >&5
+printf "%s\n" "$ac_file" >&6; }
 ac_exeext=$ac_cv_exeext
 
 rm -f -r a.out a.out.dSYM a.exe conftest$ac_cv_exeext b.out
 ac_clean_files=$ac_clean_files_save
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for suffix of executables" >&5
-$as_echo_n "checking for suffix of executables... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of executables" >&5
+printf %s "checking for suffix of executables... " >&6; }
 if { { ac_try="$ac_link"
 case "(($ac_try" in
   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_link") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; then :
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
   # If both `conftest.exe' and `conftest' are `present' (well, observable)
 # catch `conftest.exe'.  For instance with Cygwin, `ls conftest' will
 # work properly (i.e., refer to `conftest.exe'), while it won't with
@@ -2284,15 +2400,15 @@ for ac_file in conftest.exe conftest conftest.*; do
     * ) break;;
   esac
 done
-else
-  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+else $as_nop
+  { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "cannot compute suffix of executables: cannot compile and link
 See \`config.log' for more details" "$LINENO" 5; }
 fi
 rm -f conftest conftest$ac_cv_exeext
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
-$as_echo "$ac_cv_exeext" >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
+printf "%s\n" "$ac_cv_exeext" >&6; }
 
 rm -f conftest.$ac_ext
 EXEEXT=$ac_cv_exeext
@@ -2301,7 +2417,7 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <stdio.h>
 int
-main ()
+main (void)
 {
 FILE *f = fopen ("conftest.out", "w");
  return ferror (f) || fclose (f) != 0;
@@ -2313,8 +2429,8 @@ _ACEOF
 ac_clean_files="$ac_clean_files conftest.out"
 # Check that the compiler produces executables we can run.  If not, either
 # the compiler is broken, or we cross compile.
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we are cross compiling" >&5
-$as_echo_n "checking whether we are cross compiling... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether we are cross compiling" >&5
+printf %s "checking whether we are cross compiling... " >&6; }
 if test "$cross_compiling" != yes; then
   { { ac_try="$ac_link"
 case "(($ac_try" in
@@ -2322,10 +2438,10 @@ case "(($ac_try" in
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_link") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }
   if { ac_try='./conftest$ac_cv_exeext'
   { { case "(($ac_try" in
@@ -2333,39 +2449,40 @@ $as_echo "$ac_try_echo"; } >&5
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_try") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }; then
     cross_compiling=no
   else
     if test "$cross_compiling" = maybe; then
 	cross_compiling=yes
     else
-	{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error $? "cannot run C compiled programs.
+	{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "cannot run C++ compiled programs.
 If you meant to cross compile, use \`--host'.
 See \`config.log' for more details" "$LINENO" 5; }
     fi
   fi
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $cross_compiling" >&5
-$as_echo "$cross_compiling" >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $cross_compiling" >&5
+printf "%s\n" "$cross_compiling" >&6; }
 
 rm -f conftest.$ac_ext conftest$ac_cv_exeext conftest.out
 ac_clean_files=$ac_clean_files_save
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
-$as_echo_n "checking for suffix of object files... " >&6; }
-if ${ac_cv_objext+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
+printf %s "checking for suffix of object files... " >&6; }
+if test ${ac_cv_objext+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 
   ;
@@ -2379,11 +2496,12 @@ case "(($ac_try" in
   *) ac_try_echo=$ac_try;;
 esac
 eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
+printf "%s\n" "$ac_try_echo"; } >&5
   (eval "$ac_compile") 2>&5
   ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; then :
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
   for ac_file in conftest.o conftest.obj conftest.*; do
   test -f "$ac_file" || continue;
   case $ac_file in
@@ -2392,31 +2510,32 @@ $as_echo "$ac_try_echo"; } >&5
        break;;
   esac
 done
-else
-  $as_echo "$as_me: failed program was:" >&5
+else $as_nop
+  printf "%s\n" "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "cannot compute suffix of object files: cannot compile
 See \`config.log' for more details" "$LINENO" 5; }
 fi
 rm -f conftest.$ac_cv_objext conftest.$ac_ext
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_objext" >&5
-$as_echo "$ac_cv_objext" >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_objext" >&5
+printf "%s\n" "$ac_cv_objext" >&6; }
 OBJEXT=$ac_cv_objext
 ac_objext=$OBJEXT
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we are using the GNU C compiler" >&5
-$as_echo_n "checking whether we are using the GNU C compiler... " >&6; }
-if ${ac_cv_c_compiler_gnu+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports GNU C++" >&5
+printf %s "checking whether the compiler supports GNU C++... " >&6; }
+if test ${ac_cv_cxx_compiler_gnu+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 #ifndef __GNUC__
        choke me
@@ -2426,273 +2545,279 @@ main ()
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"
+then :
   ac_compiler_gnu=yes
-else
+else $as_nop
   ac_compiler_gnu=no
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-ac_cv_c_compiler_gnu=$ac_compiler_gnu
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+ac_cv_cxx_compiler_gnu=$ac_compiler_gnu
 
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_compiler_gnu" >&5
-$as_echo "$ac_cv_c_compiler_gnu" >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_cxx_compiler_gnu" >&5
+printf "%s\n" "$ac_cv_cxx_compiler_gnu" >&6; }
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+
 if test $ac_compiler_gnu = yes; then
-  GCC=yes
-else
-  GCC=
-fi
-ac_test_CFLAGS=${CFLAGS+set}
-ac_save_CFLAGS=$CFLAGS
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC accepts -g" >&5
-$as_echo_n "checking whether $CC accepts -g... " >&6; }
-if ${ac_cv_prog_cc_g+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_save_c_werror_flag=$ac_c_werror_flag
-   ac_c_werror_flag=yes
-   ac_cv_prog_cc_g=no
-   CFLAGS="-g"
+  GXX=yes
+else
+  GXX=
+fi
+ac_test_CXXFLAGS=${CXXFLAGS+y}
+ac_save_CXXFLAGS=$CXXFLAGS
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CXX accepts -g" >&5
+printf %s "checking whether $CXX accepts -g... " >&6; }
+if test ${ac_cv_prog_cxx_g+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_save_cxx_werror_flag=$ac_cxx_werror_flag
+   ac_cxx_werror_flag=yes
+   ac_cv_prog_cxx_g=no
+   CXXFLAGS="-g"
    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 
   ;
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_prog_cc_g=yes
-else
-  CFLAGS=""
+if ac_fn_cxx_try_compile "$LINENO"
+then :
+  ac_cv_prog_cxx_g=yes
+else $as_nop
+  CXXFLAGS=""
       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 
   ;
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"
+then :
 
-else
-  ac_c_werror_flag=$ac_save_c_werror_flag
-	 CFLAGS="-g"
+else $as_nop
+  ac_cxx_werror_flag=$ac_save_cxx_werror_flag
+	 CXXFLAGS="-g"
 	 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
-main ()
+main (void)
 {
 
   ;
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_prog_cc_g=yes
+if ac_fn_cxx_try_compile "$LINENO"
+then :
+  ac_cv_prog_cxx_g=yes
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-   ac_c_werror_flag=$ac_save_c_werror_flag
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ac_cxx_werror_flag=$ac_save_cxx_werror_flag
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_g" >&5
-$as_echo "$ac_cv_prog_cc_g" >&6; }
-if test "$ac_test_CFLAGS" = set; then
-  CFLAGS=$ac_save_CFLAGS
-elif test $ac_cv_prog_cc_g = yes; then
-  if test "$GCC" = yes; then
-    CFLAGS="-g -O2"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cxx_g" >&5
+printf "%s\n" "$ac_cv_prog_cxx_g" >&6; }
+if test $ac_test_CXXFLAGS; then
+  CXXFLAGS=$ac_save_CXXFLAGS
+elif test $ac_cv_prog_cxx_g = yes; then
+  if test "$GXX" = yes; then
+    CXXFLAGS="-g -O2"
   else
-    CFLAGS="-g"
+    CXXFLAGS="-g"
   fi
 else
-  if test "$GCC" = yes; then
-    CFLAGS="-O2"
+  if test "$GXX" = yes; then
+    CXXFLAGS="-O2"
   else
-    CFLAGS=
+    CXXFLAGS=
   fi
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
-$as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
-if ${ac_cv_prog_cc_c89+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_cv_prog_cc_c89=no
-ac_save_CC=$CC
+ac_prog_cxx_stdcxx=no
+if test x$ac_prog_cxx_stdcxx = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++11 features" >&5
+printf %s "checking for $CXX option to enable C++11 features... " >&6; }
+if test ${ac_cv_prog_cxx_11+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_cv_prog_cxx_11=no
+ac_save_CXX=$CXX
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <stdarg.h>
-#include <stdio.h>
-struct stat;
-/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
-struct buf { int x; };
-FILE * (*rcsopen) (struct buf *, struct stat *, int);
-static char *e (p, i)
-     char **p;
-     int i;
-{
-  return p[i];
-}
-static char *f (char * (*g) (char **, int), char **p, ...)
-{
-  char *s;
-  va_list v;
-  va_start (v,p);
-  s = g (p, va_arg (v,int));
-  va_end (v);
-  return s;
-}
-
-/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
-   function prototypes and stuff, but not '\xHH' hex character constants.
-   These don't provoke an error unfortunately, instead are silently treated
-   as 'x'.  The following induces an error, until -std is added to get
-   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
-   array size at least.  It's necessary to write '\x00'==0 to get something
-   that's true only with -std.  */
-int osf4_cc_array ['\x00' == 0 ? 1 : -1];
-
-/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
-   inside strings and character constants.  */
-#define FOO(x) 'x'
-int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];
-
-int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};
-int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
-int argc;
-char **argv;
-int
-main ()
-{
-return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
-  ;
-  return 0;
-}
+$ac_cxx_conftest_cxx11_program
 _ACEOF
-for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std \
-	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+for ac_arg in '' -std=gnu++11 -std=gnu++0x -std=c++11 -std=c++0x -qlanglvl=extended0x -AA
 do
-  CC="$ac_save_CC $ac_arg"
-  if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_prog_cc_c89=$ac_arg
+  CXX="$ac_save_CXX $ac_arg"
+  if ac_fn_cxx_try_compile "$LINENO"
+then :
+  ac_cv_prog_cxx_cxx11=$ac_arg
 fi
-rm -f core conftest.err conftest.$ac_objext
-  test "x$ac_cv_prog_cc_c89" != "xno" && break
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cxx_cxx11" != "xno" && break
 done
 rm -f conftest.$ac_ext
-CC=$ac_save_CC
-
+CXX=$ac_save_CXX
+fi
+
+if test "x$ac_cv_prog_cxx_cxx11" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else $as_nop
+  if test "x$ac_cv_prog_cxx_cxx11" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cxx_cxx11" >&5
+printf "%s\n" "$ac_cv_prog_cxx_cxx11" >&6; }
+     CXX="$CXX $ac_cv_prog_cxx_cxx11"
+fi
+  ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx11
+  ac_prog_cxx_stdcxx=cxx11
+fi
+fi
+if test x$ac_prog_cxx_stdcxx = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++98 features" >&5
+printf %s "checking for $CXX option to enable C++98 features... " >&6; }
+if test ${ac_cv_prog_cxx_98+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_cv_prog_cxx_98=no
+ac_save_CXX=$CXX
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_cxx_conftest_cxx98_program
+_ACEOF
+for ac_arg in '' -std=gnu++98 -std=c++98 -qlanglvl=extended -AA
+do
+  CXX="$ac_save_CXX $ac_arg"
+  if ac_fn_cxx_try_compile "$LINENO"
+then :
+  ac_cv_prog_cxx_cxx98=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cxx_cxx98" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CXX=$ac_save_CXX
 fi
-# AC_CACHE_VAL
-case "x$ac_cv_prog_cc_c89" in
-  x)
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
-$as_echo "none needed" >&6; } ;;
-  xno)
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
-$as_echo "unsupported" >&6; } ;;
-  *)
-    CC="$CC $ac_cv_prog_cc_c89"
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
-$as_echo "$ac_cv_prog_cc_c89" >&6; } ;;
-esac
-if test "x$ac_cv_prog_cc_c89" != xno; then :
 
+if test "x$ac_cv_prog_cxx_cxx98" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else $as_nop
+  if test "x$ac_cv_prog_cxx_cxx98" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cxx_cxx98" >&5
+printf "%s\n" "$ac_cv_prog_cxx_cxx98" >&6; }
+     CXX="$CXX $ac_cv_prog_cxx_cxx98"
+fi
+  ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx98
+  ac_prog_cxx_stdcxx=cxx98
+fi
 fi
 
-ac_ext=c
-ac_cpp='$CPP $CPPFLAGS'
-ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_c_compiler_gnu
+ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 
-### Check whether backtrace() is part of libc or the external lib libexecinfo
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking Backtrace lib" >&5
-$as_echo_n "checking Backtrace lib... " >&6; }
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: " >&5
-$as_echo "" >&6; }
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for backtrace in -lexecinfo" >&5
-$as_echo_n "checking for backtrace in -lexecinfo... " >&6; }
-if ${ac_cv_lib_execinfo_backtrace+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for backtrace in -lexecinfo" >&5
+printf %s "checking for backtrace in -lexecinfo... " >&6; }
+if test ${ac_cv_lib_execinfo_backtrace+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
   ac_check_lib_save_LIBS=$LIBS
 LIBS="-lexecinfo  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char backtrace ();
+namespace conftest {
+  extern "C" int backtrace ();
+}
 int
-main ()
+main (void)
 {
-return backtrace ();
+return conftest::backtrace ();
   ;
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
+if ac_fn_cxx_try_link "$LINENO"
+then :
   ac_cv_lib_execinfo_backtrace=yes
-else
+else $as_nop
   ac_cv_lib_execinfo_backtrace=no
 fi
-rm -f core conftest.err conftest.$ac_objext \
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_execinfo_backtrace" >&5
-$as_echo "$ac_cv_lib_execinfo_backtrace" >&6; }
-if test "x$ac_cv_lib_execinfo_backtrace" = xyes; then :
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_execinfo_backtrace" >&5
+printf "%s\n" "$ac_cv_lib_execinfo_backtrace" >&6; }
+if test "x$ac_cv_lib_execinfo_backtrace" = xyes
+then :
   BACKTRACE_LIB=-lexecinfo
-else
+else $as_nop
   BACKTRACE_LIB=''
 fi
 
 
 ### Endian detection
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking endian" >&5
-$as_echo_n "checking endian... " >&6; }
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: " >&5
-$as_echo "" >&6; }
-if test "$cross_compiling" = yes; then :
-  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking endian" >&5
+printf %s "checking endian... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: " >&5
+printf "%s\n" "" >&6; }
+if test "$cross_compiling" = yes
+then :
+  { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "cannot run test program while cross compiling
 See \`config.log' for more details" "$LINENO" 5; }
-else
+else $as_nop
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <stdint.h>
 int
-main ()
+main (void)
 {
 const uint16_t endianness = 256; return !!(*(const uint8_t *)&endianness);
   ;
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_run "$LINENO"; then :
+if ac_fn_cxx_try_run "$LINENO"
+then :
   ENDIAN_FLAG="-DDMLC_CMAKE_LITTLE_ENDIAN=1"
-else
+else $as_nop
   ENDIAN_FLAG="-DDMLC_CMAKE_LITTLE_ENDIAN=0"
 fi
 rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
@@ -2709,25 +2834,32 @@ fi
 
 if test `uname -s` = "Darwin"
 then
-  OPENMP_CXXFLAGS='-Xclang -fopenmp'
-  OPENMP_LIB='-lomp'
+  if command -v brew &> /dev/null
+  then
+    HOMEBREW_LIBOMP_PREFIX=`brew --prefix libomp`
+  else
+    # Homebrew not found
+    HOMEBREW_LIBOMP_PREFIX=''
+  fi
+  OPENMP_CXXFLAGS="-Xpreprocessor -fopenmp -I${HOMEBREW_LIBOMP_PREFIX}/include"
+  OPENMP_LIB="-lomp -L${HOMEBREW_LIBOMP_PREFIX}/lib"
   ac_pkg_openmp=no
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether OpenMP will work in a package" >&5
-$as_echo_n "checking whether OpenMP will work in a package... " >&6; }
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether OpenMP will work in a package" >&5
+printf %s "checking whether OpenMP will work in a package... " >&6; }
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <omp.h>
 int
-main ()
+main (void)
 {
  return (omp_get_max_threads() <= 1);
   ;
   return 0;
 }
 _ACEOF
-  ${CC} -o conftest conftest.c ${CPPFLAGS} ${LDFLAGS} ${OPENMP_LIB} ${OPENMP_CXXFLAGS} 2>/dev/null && ./conftest && ac_pkg_openmp=yes
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: ${ac_pkg_openmp}" >&5
-$as_echo "${ac_pkg_openmp}" >&6; }
+  ${CXX} -o conftest conftest.cpp ${CPPFLAGS} ${LDFLAGS} ${OPENMP_LIB} ${OPENMP_CXXFLAGS} 2>/dev/null && ./conftest && ac_pkg_openmp=yes
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: ${ac_pkg_openmp}" >&5
+printf "%s\n" "${ac_pkg_openmp}" >&6; }
   if test "${ac_pkg_openmp}" = no; then
     OPENMP_CXXFLAGS=''
     OPENMP_LIB=''
@@ -2772,8 +2904,8 @@ _ACEOF
     case $ac_val in #(
     *${as_nl}*)
       case $ac_var in #(
-      *_cv_*) { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
-$as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
       esac
       case $ac_var in #(
       _ | IFS | as_nl) ;; #(
@@ -2803,15 +2935,15 @@ $as_echo "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
      /^ac_cv_env_/b end
      t clear
      :clear
-     s/^\([^=]*\)=\(.*[{}].*\)$/test "${\1+set}" = set || &/
+     s/^\([^=]*\)=\(.*[{}].*\)$/test ${\1+y} || &/
      t end
      s/^\([^=]*\)=\(.*\)$/\1=${\1=\2}/
      :end' >>confcache
 if diff "$cache_file" confcache >/dev/null 2>&1; then :; else
   if test -w "$cache_file"; then
     if test "x$cache_file" != "x/dev/null"; then
-      { $as_echo "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
-$as_echo "$as_me: updating cache $cache_file" >&6;}
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
+printf "%s\n" "$as_me: updating cache $cache_file" >&6;}
       if test ! -f "$cache_file" || test -h "$cache_file"; then
 	cat confcache >"$cache_file"
       else
@@ -2825,8 +2957,8 @@ $as_echo "$as_me: updating cache $cache_file" >&6;}
       fi
     fi
   else
-    { $as_echo "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
-$as_echo "$as_me: not updating unwritable cache $cache_file" >&6;}
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
+printf "%s\n" "$as_me: not updating unwritable cache $cache_file" >&6;}
   fi
 fi
 rm -f confcache
@@ -2879,7 +3011,7 @@ U=
 for ac_i in : $LIBOBJS; do test "x$ac_i" = x: && continue
   # 1. Remove the extension, and $U if already installed.
   ac_script='s/\$U\././;s/\.o$//;s/\.obj$//'
-  ac_i=`$as_echo "$ac_i" | sed "$ac_script"`
+  ac_i=`printf "%s\n" "$ac_i" | sed "$ac_script"`
   # 2. Prepend LIBOBJDIR.  When used with automake>=1.10 LIBOBJDIR
   #    will be set to the directory where LIBOBJS objects are built.
   as_fn_append ac_libobjs " \${LIBOBJDIR}$ac_i\$U.$ac_objext"
@@ -2895,8 +3027,8 @@ LTLIBOBJS=$ac_ltlibobjs
 ac_write_fail=0
 ac_clean_files_save=$ac_clean_files
 ac_clean_files="$ac_clean_files $CONFIG_STATUS"
-{ $as_echo "$as_me:${as_lineno-$LINENO}: creating $CONFIG_STATUS" >&5
-$as_echo "$as_me: creating $CONFIG_STATUS" >&6;}
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $CONFIG_STATUS" >&5
+printf "%s\n" "$as_me: creating $CONFIG_STATUS" >&6;}
 as_write_fail=0
 cat >$CONFIG_STATUS <<_ASEOF || as_write_fail=1
 #! $SHELL
@@ -2919,14 +3051,16 @@ cat >>$CONFIG_STATUS <<\_ASEOF || as_write_fail=1
 
 # Be more Bourne compatible
 DUALCASE=1; export DUALCASE # for MKS sh
-if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+as_nop=:
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
   emulate sh
   NULLCMD=:
   # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
   # is contrary to our usage.  Disable this feature.
   alias -g '${1+"$@"}'='"$@"'
   setopt NO_GLOB_SUBST
-else
+else $as_nop
   case `(set -o) 2>/dev/null` in #(
   *posix*) :
     set -o posix ;; #(
@@ -2936,46 +3070,46 @@ esac
 fi
 
 
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
 as_nl='
 '
 export as_nl
-# Printing a long string crashes Solaris 7 /usr/bin/printf.
-as_echo='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
-as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo
-as_echo=$as_echo$as_echo$as_echo$as_echo$as_echo$as_echo
-# Prefer a ksh shell builtin over an external printf program on Solaris,
-# but without wasting forks for bash or zsh.
-if test -z "$BASH_VERSION$ZSH_VERSION" \
-    && (test "X`print -r -- $as_echo`" = "X$as_echo") 2>/dev/null; then
-  as_echo='print -r --'
-  as_echo_n='print -rn --'
-elif (test "X`printf %s $as_echo`" = "X$as_echo") 2>/dev/null; then
-  as_echo='printf %s\n'
-  as_echo_n='printf %s'
-else
-  if test "X`(/usr/ucb/echo -n -n $as_echo) 2>/dev/null`" = "X-n $as_echo"; then
-    as_echo_body='eval /usr/ucb/echo -n "$1$as_nl"'
-    as_echo_n='/usr/ucb/echo -n'
-  else
-    as_echo_body='eval expr "X$1" : "X\\(.*\\)"'
-    as_echo_n_body='eval
-      arg=$1;
-      case $arg in #(
-      *"$as_nl"*)
-	expr "X$arg" : "X\\(.*\\)$as_nl";
-	arg=`expr "X$arg" : ".*$as_nl\\(.*\\)"`;;
-      esac;
-      expr "X$arg" : "X\\(.*\\)" | tr -d "$as_nl"
-    '
-    export as_echo_n_body
-    as_echo_n='sh -c $as_echo_n_body as_echo'
-  fi
-  export as_echo_body
-  as_echo='sh -c $as_echo_body as_echo'
-fi
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
 
 # The user is always right.
-if test "${PATH_SEPARATOR+set}" != set; then
+if ${PATH_SEPARATOR+false} :; then
   PATH_SEPARATOR=:
   (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
     (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
@@ -2984,13 +3118,6 @@ if test "${PATH_SEPARATOR+set}" != set; then
 fi
 
 
-# IFS
-# We need space, tab and new line, in precisely that order.  Quoting is
-# there to prevent editors from complaining about space-tab.
-# (If _AS_PATH_WALK were called with IFS unset, it would disable word
-# splitting by setting IFS to empty value.)
-IFS=" ""	$as_nl"
-
 # Find who we are.  Look in the path if we contain no directory separator.
 as_myself=
 case $0 in #((
@@ -2999,8 +3126,12 @@ case $0 in #((
 for as_dir in $PATH
 do
   IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    test -r "$as_dir/$0" && as_myself=$as_dir/$0 && break
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
   done
 IFS=$as_save_IFS
 
@@ -3012,30 +3143,10 @@ if test "x$as_myself" = x; then
   as_myself=$0
 fi
 if test ! -f "$as_myself"; then
-  $as_echo "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
   exit 1
 fi
 
-# Unset variables that we do not need and which cause bugs (e.g. in
-# pre-3.0 UWIN ksh).  But do not cause bugs in bash 2.01; the "|| exit 1"
-# suppresses any "Segmentation fault" message there.  '((' could
-# trigger a bug in pdksh 5.2.14.
-for as_var in BASH_ENV ENV MAIL MAILPATH
-do eval test x\${$as_var+set} = xset \
-  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
-done
-PS1='$ '
-PS2='> '
-PS4='+ '
-
-# NLS nuisances.
-LC_ALL=C
-export LC_ALL
-LANGUAGE=C
-export LANGUAGE
-
-# CDPATH.
-(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
 
 
 # as_fn_error STATUS ERROR [LINENO LOG_FD]
@@ -3048,13 +3159,14 @@ as_fn_error ()
   as_status=$1; test $as_status -eq 0 && as_status=1
   if test "$4"; then
     as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
   fi
-  $as_echo "$as_me: error: $2" >&2
+  printf "%s\n" "$as_me: error: $2" >&2
   as_fn_exit $as_status
 } # as_fn_error
 
 
+
 # as_fn_set_status STATUS
 # -----------------------
 # Set $? to STATUS, without forking.
@@ -3081,18 +3193,20 @@ as_fn_unset ()
   { eval $1=; unset $1;}
 }
 as_unset=as_fn_unset
+
 # as_fn_append VAR VALUE
 # ----------------------
 # Append the text in VALUE to the end of the definition contained in VAR. Take
 # advantage of any shell optimizations that allow amortized linear growth over
 # repeated appends, instead of the typical quadratic growth present in naive
 # implementations.
-if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null; then :
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
   eval 'as_fn_append ()
   {
     eval $1+=\$2
   }'
-else
+else $as_nop
   as_fn_append ()
   {
     eval $1=\$$1\$2
@@ -3104,12 +3218,13 @@ fi # as_fn_append
 # Perform arithmetic evaluation on the ARGs, and store the result in the
 # global $as_val. Take advantage of shells that can avoid forks. The arguments
 # must be portable across $(()) and expr.
-if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null; then :
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
   eval 'as_fn_arith ()
   {
     as_val=$(( $* ))
   }'
-else
+else $as_nop
   as_fn_arith ()
   {
     as_val=`expr "$@" || test $? -eq 1`
@@ -3140,7 +3255,7 @@ as_me=`$as_basename -- "$0" ||
 $as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
 	 X"$0" : 'X\(//\)$' \| \
 	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X/"$0" |
+printf "%s\n" X/"$0" |
     sed '/^.*\/\([^/][^/]*\)\/*$/{
 	    s//\1/
 	    q
@@ -3162,6 +3277,10 @@ as_cr_Letters=$as_cr_letters$as_cr_LETTERS
 as_cr_digits='0123456789'
 as_cr_alnum=$as_cr_Letters$as_cr_digits
 
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
 ECHO_C= ECHO_N= ECHO_T=
 case `echo -n x` in #(((((
 -n*)
@@ -3175,6 +3294,12 @@ case `echo -n x` in #(((((
   ECHO_N='-n';;
 esac
 
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
 rm -f conf$$ conf$$.exe conf$$.file
 if test -d conf$$.dir; then
   rm -f conf$$.dir/conf$$.file
@@ -3216,7 +3341,7 @@ as_fn_mkdir_p ()
     as_dirs=
     while :; do
       case $as_dir in #(
-      *\'*) as_qdir=`$as_echo "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
       *) as_qdir=$as_dir;;
       esac
       as_dirs="'$as_qdir' $as_dirs"
@@ -3225,7 +3350,7 @@ $as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
 	 X"$as_dir" : 'X\(//\)[^/]' \| \
 	 X"$as_dir" : 'X\(//\)$' \| \
 	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X"$as_dir" |
+printf "%s\n" X"$as_dir" |
     sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
 	    s//\1/
 	    q
@@ -3287,8 +3412,8 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by xgboost $as_me 1.7.0, which was
-generated by GNU Autoconf 2.69.  Invocation command line was
+This file was extended by xgboost $as_me 1.7.5, which was
+generated by GNU Autoconf 2.71.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
   CONFIG_HEADERS  = $CONFIG_HEADERS
@@ -3337,14 +3462,16 @@ $config_files
 Report bugs to the package provider."
 
 _ACEOF
+ac_cs_config=`printf "%s\n" "$ac_configure_args" | sed "$ac_safe_unquote"`
+ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\''/g"`
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
-ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
+ac_cs_config='$ac_cs_config_escaped'
 ac_cs_version="\\
-xgboost config.status 1.7.0
-configured by $0, generated by GNU Autoconf 2.69,
+xgboost config.status 1.7.5
+configured by $0, generated by GNU Autoconf 2.71,
   with options \\"\$ac_cs_config\\"
 
-Copyright (C) 2012 Free Software Foundation, Inc.
+Copyright (C) 2021 Free Software Foundation, Inc.
 This config.status script is free software; the Free Software Foundation
 gives unlimited permission to copy, distribute and modify it."
 
@@ -3381,21 +3508,21 @@ do
   -recheck | --recheck | --rechec | --reche | --rech | --rec | --re | --r)
     ac_cs_recheck=: ;;
   --version | --versio | --versi | --vers | --ver | --ve | --v | -V )
-    $as_echo "$ac_cs_version"; exit ;;
+    printf "%s\n" "$ac_cs_version"; exit ;;
   --config | --confi | --conf | --con | --co | --c )
-    $as_echo "$ac_cs_config"; exit ;;
+    printf "%s\n" "$ac_cs_config"; exit ;;
   --debug | --debu | --deb | --de | --d | -d )
     debug=: ;;
   --file | --fil | --fi | --f )
     $ac_shift
     case $ac_optarg in
-    *\'*) ac_optarg=`$as_echo "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    *\'*) ac_optarg=`printf "%s\n" "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
     '') as_fn_error $? "missing file argument" ;;
     esac
     as_fn_append CONFIG_FILES " '$ac_optarg'"
     ac_need_defaults=false;;
   --he | --h |  --help | --hel | -h )
-    $as_echo "$ac_cs_usage"; exit ;;
+    printf "%s\n" "$ac_cs_usage"; exit ;;
   -q | -quiet | --quiet | --quie | --qui | --qu | --q \
   | -silent | --silent | --silen | --sile | --sil | --si | --s)
     ac_cs_silent=: ;;
@@ -3423,7 +3550,7 @@ cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 if \$ac_cs_recheck; then
   set X $SHELL '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion
   shift
-  \$as_echo "running CONFIG_SHELL=$SHELL \$*" >&6
+  \printf "%s\n" "running CONFIG_SHELL=$SHELL \$*" >&6
   CONFIG_SHELL='$SHELL'
   export CONFIG_SHELL
   exec "\$@"
@@ -3437,7 +3564,7 @@ exec 5>>config.log
   sed 'h;s/./-/g;s/^.../## /;s/...$/ ##/;p;x;p;x' <<_ASBOX
 ## Running $as_me. ##
 _ASBOX
-  $as_echo "$ac_log"
+  printf "%s\n" "$ac_log"
 } >&5
 
 _ACEOF
@@ -3462,7 +3589,7 @@ done
 # We use the long form for the default assignment because of an extremely
 # bizarre bug on SunOS 4.1.3.
 if $ac_need_defaults; then
-  test "${CONFIG_FILES+set}" = set || CONFIG_FILES=$config_files
+  test ${CONFIG_FILES+y} || CONFIG_FILES=$config_files
 fi
 
 # Have a temporary directory for convenience.  Make it in the build tree
@@ -3690,7 +3817,7 @@ do
 	   esac ||
 	   as_fn_error 1 "cannot find input file: \`$ac_f'" "$LINENO" 5;;
       esac
-      case $ac_f in *\'*) ac_f=`$as_echo "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
+      case $ac_f in *\'*) ac_f=`printf "%s\n" "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
       as_fn_append ac_file_inputs " '$ac_f'"
     done
 
@@ -3698,17 +3825,17 @@ do
     # use $as_me), people would be surprised to read:
     #    /* config.h.  Generated by config.status.  */
     configure_input='Generated from '`
-	  $as_echo "$*" | sed 's|^[^:]*/||;s|:[^:]*/|, |g'
+	  printf "%s\n" "$*" | sed 's|^[^:]*/||;s|:[^:]*/|, |g'
 	`' by configure.'
     if test x"$ac_file" != x-; then
       configure_input="$ac_file.  $configure_input"
-      { $as_echo "$as_me:${as_lineno-$LINENO}: creating $ac_file" >&5
-$as_echo "$as_me: creating $ac_file" >&6;}
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $ac_file" >&5
+printf "%s\n" "$as_me: creating $ac_file" >&6;}
     fi
     # Neutralize special characters interpreted by sed in replacement strings.
     case $configure_input in #(
     *\&* | *\|* | *\\* )
-       ac_sed_conf_input=`$as_echo "$configure_input" |
+       ac_sed_conf_input=`printf "%s\n" "$configure_input" |
        sed 's/[\\\\&|]/\\\\&/g'`;; #(
     *) ac_sed_conf_input=$configure_input;;
     esac
@@ -3725,7 +3852,7 @@ $as_expr X"$ac_file" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
 	 X"$ac_file" : 'X\(//\)[^/]' \| \
 	 X"$ac_file" : 'X\(//\)$' \| \
 	 X"$ac_file" : 'X\(/\)' \| . 2>/dev/null ||
-$as_echo X"$ac_file" |
+printf "%s\n" X"$ac_file" |
     sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
 	    s//\1/
 	    q
@@ -3749,9 +3876,9 @@ $as_echo X"$ac_file" |
 case "$ac_dir" in
 .) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
 *)
-  ac_dir_suffix=/`$as_echo "$ac_dir" | sed 's|^\.[\\/]||'`
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
   # A ".." for each directory in $ac_dir_suffix.
-  ac_top_builddir_sub=`$as_echo "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
   case $ac_top_builddir_sub in
   "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
   *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
@@ -3804,8 +3931,8 @@ ac_sed_dataroot='
 case `eval "sed -n \"\$ac_sed_dataroot\" $ac_file_inputs"` in
 *datarootdir*) ac_datarootdir_seen=yes;;
 *@datadir@*|*@docdir@*|*@infodir@*|*@localedir@*|*@mandir@*)
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&5
-$as_echo "$as_me: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&2;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&5
+printf "%s\n" "$as_me: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&2;}
 _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
   ac_datarootdir_hack='
@@ -3847,9 +3974,9 @@ test -z "$ac_datarootdir_hack$ac_datarootdir_seen" &&
   { ac_out=`sed -n '/\${datarootdir}/p' "$ac_tmp/out"`; test -n "$ac_out"; } &&
   { ac_out=`sed -n '/^[	 ]*datarootdir[	 ]*:*=/p' \
       "$ac_tmp/out"`; test -z "$ac_out"; } &&
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file contains a reference to the variable \`datarootdir'
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined" >&5
-$as_echo "$as_me: WARNING: $ac_file contains a reference to the variable \`datarootdir'
+printf "%s\n" "$as_me: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined" >&2;}
 
   rm -f "$ac_tmp/stdin"
@@ -3896,7 +4023,8 @@ if test "$no_create" != yes; then
   $ac_cs_success || as_fn_exit 1
 fi
 if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
-$as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
+printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
 fi
 
+
diff --git a/R-package/configure.ac b/R-package/configure.ac
index 8be57fee79f3..e78baad137be 100644
--- a/R-package/configure.ac
+++ b/R-package/configure.ac
@@ -2,10 +2,25 @@
 
 AC_PREREQ(2.69)
 
-AC_INIT([xgboost],[1.7.0],[],[xgboost],[])
+AC_INIT([xgboost],[1.7.5],[],[xgboost],[])
 
-# Use this line to set CC variable to a C compiler
-AC_PROG_CC
+: ${R_HOME=`R RHOME`}
+if test -z "${R_HOME}"; then
+  echo "could not determine R_HOME"
+  exit 1
+fi
+
+CXX17=`"${R_HOME}/bin/R" CMD config CXX17`
+CXX17STD=`"${R_HOME}/bin/R" CMD config CXX17STD`
+CXX="${CXX17} ${CXX17STD}"
+CXXFLAGS=`"${R_HOME}/bin/R" CMD config CXXFLAGS`
+
+CC=`"${R_HOME}/bin/R" CMD config CC`
+CFLAGS=`"${R_HOME}/bin/R" CMD config CFLAGS`
+CPPFLAGS=`"${R_HOME}/bin/R" CMD config CPPFLAGS`
+
+LDFLAGS=`"${R_HOME}/bin/R" CMD config LDFLAGS`
+AC_LANG(C++)
 
 ### Check whether backtrace() is part of libc or the external lib libexecinfo
 AC_MSG_CHECKING([Backtrace lib])
@@ -28,12 +43,19 @@ fi
 
 if test `uname -s` = "Darwin"
 then
-  OPENMP_CXXFLAGS='-Xclang -fopenmp'
-  OPENMP_LIB='-lomp'
+  if command -v brew &> /dev/null
+  then
+    HOMEBREW_LIBOMP_PREFIX=`brew --prefix libomp`
+  else
+    # Homebrew not found
+    HOMEBREW_LIBOMP_PREFIX=''
+  fi
+  OPENMP_CXXFLAGS="-Xpreprocessor -fopenmp -I${HOMEBREW_LIBOMP_PREFIX}/include"
+  OPENMP_LIB="-lomp -L${HOMEBREW_LIBOMP_PREFIX}/lib"
   ac_pkg_openmp=no
   AC_MSG_CHECKING([whether OpenMP will work in a package])
   AC_LANG_CONFTEST([AC_LANG_PROGRAM([[#include <omp.h>]], [[ return (omp_get_max_threads() <= 1); ]])])
-  ${CC} -o conftest conftest.c ${CPPFLAGS} ${LDFLAGS} ${OPENMP_LIB} ${OPENMP_CXXFLAGS} 2>/dev/null && ./conftest && ac_pkg_openmp=yes
+  ${CXX} -o conftest conftest.cpp ${CPPFLAGS} ${LDFLAGS} ${OPENMP_LIB} ${OPENMP_CXXFLAGS} 2>/dev/null && ./conftest && ac_pkg_openmp=yes
   AC_MSG_RESULT([${ac_pkg_openmp}])
   if test "${ac_pkg_openmp}" = no; then
     OPENMP_CXXFLAGS=''
diff --git a/R-package/man/cb.gblinear.history.Rd b/R-package/man/cb.gblinear.history.Rd
index b111bd41dda1..fbbb56dbefc6 100644
--- a/R-package/man/cb.gblinear.history.Rd
+++ b/R-package/man/cb.gblinear.history.Rd
@@ -15,9 +15,11 @@ selected per iteration.}
 }
 \value{
 Results are stored in the \code{coefs} element of the closure.
-The \code{\link{xgb.gblinear.history}} convenience function provides an easy way to access it.
+The \code{\link{xgb.gblinear.history}} convenience function provides an easy
+way to access it.
 With \code{xgb.train}, it is either a dense of a sparse matrix.
-While with \code{xgb.cv}, it is a list (an element per each fold) of such matrices.
+While with \code{xgb.cv}, it is a list (an element per each fold) of such
+matrices.
 }
 \description{
 Callback closure for collecting the model coefficients history of a gblinear booster
@@ -38,7 +40,7 @@ Callback function expects the following values to be set in its calling frame:
 # without considering the 2nd order interactions:
 x <- model.matrix(Species ~ .^2, iris)[,-1]
 colnames(x)
-dtrain <- xgb.DMatrix(scale(x), label = 1*(iris$Species == "versicolor"))
+dtrain <- xgb.DMatrix(scale(x), label = 1*(iris$Species == "versicolor"), nthread = 2)
 param <- list(booster = "gblinear", objective = "reg:logistic", eval_metric = "auc",
               lambda = 0.0003, alpha = 0.0003, nthread = 2)
 # For 'shotgun', which is a default linear updater, using high eta values may result in
@@ -63,14 +65,14 @@ matplot(xgb.gblinear.history(bst), type = 'l')
 
 # For xgb.cv:
 bst <- xgb.cv(param, dtrain, nfold = 5, nrounds = 100, eta = 0.8,
-             callbacks = list(cb.gblinear.history()))
+              callbacks = list(cb.gblinear.history()))
 # coefficients in the CV fold #3
 matplot(xgb.gblinear.history(bst)[[3]], type = 'l')
 
 
 #### Multiclass classification:
 #
-dtrain <- xgb.DMatrix(scale(x), label = as.numeric(iris$Species) - 1)
+dtrain <- xgb.DMatrix(scale(x), label = as.numeric(iris$Species) - 1, nthread = 2)
 param <- list(booster = "gblinear", objective = "multi:softprob", num_class = 3,
               lambda = 0.0003, alpha = 0.0003, nthread = 2)
 # For the default linear updater 'shotgun' it sometimes is helpful
diff --git a/R-package/man/dim.xgb.DMatrix.Rd b/R-package/man/dim.xgb.DMatrix.Rd
index 76c53dec2614..c9ea79177da3 100644
--- a/R-package/man/dim.xgb.DMatrix.Rd
+++ b/R-package/man/dim.xgb.DMatrix.Rd
@@ -19,7 +19,7 @@ be directly used with an \code{xgb.DMatrix} object.
 \examples{
 data(agaricus.train, package='xgboost')
 train <- agaricus.train
-dtrain <- xgb.DMatrix(train$data, label=train$label)
+dtrain <- xgb.DMatrix(train$data, label=train$label, nthread = 2)
 
 stopifnot(nrow(dtrain) == nrow(train$data))
 stopifnot(ncol(dtrain) == ncol(train$data))
diff --git a/R-package/man/dimnames.xgb.DMatrix.Rd b/R-package/man/dimnames.xgb.DMatrix.Rd
index 032cb95a55dd..9f2a07d8d592 100644
--- a/R-package/man/dimnames.xgb.DMatrix.Rd
+++ b/R-package/man/dimnames.xgb.DMatrix.Rd
@@ -26,7 +26,7 @@ Since row names are irrelevant, it is recommended to use \code{colnames} directl
 \examples{
 data(agaricus.train, package='xgboost')
 train <- agaricus.train
-dtrain <- xgb.DMatrix(train$data, label=train$label)
+dtrain <- xgb.DMatrix(train$data, label=train$label, nthread = 2)
 dimnames(dtrain)
 colnames(dtrain)
 colnames(dtrain) <- make.names(1:ncol(train$data))
diff --git a/R-package/man/getinfo.Rd b/R-package/man/getinfo.Rd
index 246860bbd3f4..63222f3412c4 100644
--- a/R-package/man/getinfo.Rd
+++ b/R-package/man/getinfo.Rd
@@ -34,7 +34,7 @@ The \code{name} field can be one of the following:
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 
 labels <- getinfo(dtrain, 'label')
 setinfo(dtrain, 'label', 1-labels)
diff --git a/R-package/man/print.xgb.DMatrix.Rd b/R-package/man/print.xgb.DMatrix.Rd
index f6cb2f62bea6..72c3d35e9043 100644
--- a/R-package/man/print.xgb.DMatrix.Rd
+++ b/R-package/man/print.xgb.DMatrix.Rd
@@ -19,7 +19,7 @@ Currently it displays dimensions and presence of info-fields and colnames.
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 
 dtrain
 print(dtrain, verbose=TRUE)
diff --git a/R-package/man/setinfo.Rd b/R-package/man/setinfo.Rd
index 696a04c2ddea..c29fcfa7e976 100644
--- a/R-package/man/setinfo.Rd
+++ b/R-package/man/setinfo.Rd
@@ -33,7 +33,7 @@ The \code{name} field can be one of the following:
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 
 labels <- getinfo(dtrain, 'label')
 setinfo(dtrain, 'label', 1-labels)
diff --git a/R-package/man/slice.xgb.DMatrix.Rd b/R-package/man/slice.xgb.DMatrix.Rd
index 5fffc203410a..cb65083e2aa2 100644
--- a/R-package/man/slice.xgb.DMatrix.Rd
+++ b/R-package/man/slice.xgb.DMatrix.Rd
@@ -28,7 +28,7 @@ original xgb.DMatrix object
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 
 dsub <- slice(dtrain, 1:42)
 labels1 <- getinfo(dsub, 'label')
diff --git a/R-package/man/xgb.DMatrix.Rd b/R-package/man/xgb.DMatrix.Rd
index 52a31cfd1435..742073faddc4 100644
--- a/R-package/man/xgb.DMatrix.Rd
+++ b/R-package/man/xgb.DMatrix.Rd
@@ -38,7 +38,7 @@ Supported input file formats are either a LIBSVM text file or a binary file that
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 xgb.DMatrix.save(dtrain, 'xgb.DMatrix.data')
 dtrain <- xgb.DMatrix('xgb.DMatrix.data')
 if (file.exists('xgb.DMatrix.data')) file.remove('xgb.DMatrix.data')
diff --git a/R-package/man/xgb.DMatrix.save.Rd b/R-package/man/xgb.DMatrix.save.Rd
index 63e6930a874b..40151605954f 100644
--- a/R-package/man/xgb.DMatrix.save.Rd
+++ b/R-package/man/xgb.DMatrix.save.Rd
@@ -16,7 +16,7 @@ Save xgb.DMatrix object to binary file
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 xgb.DMatrix.save(dtrain, 'xgb.DMatrix.data')
 dtrain <- xgb.DMatrix('xgb.DMatrix.data')
 if (file.exists('xgb.DMatrix.data')) file.remove('xgb.DMatrix.data')
diff --git a/R-package/man/xgb.create.features.Rd b/R-package/man/xgb.create.features.Rd
index 52ac052cb71d..64d4af158ef3 100644
--- a/R-package/man/xgb.create.features.Rd
+++ b/R-package/man/xgb.create.features.Rd
@@ -59,8 +59,8 @@ a rule on certain features."
 \examples{
 data(agaricus.train, package='xgboost')
 data(agaricus.test, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
-dtest <- with(agaricus.test, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
+dtest <- with(agaricus.test, xgb.DMatrix(data, label = label, nthread = 2))
 
 param <- list(max_depth=2, eta=1, silent=1, objective='binary:logistic')
 nrounds = 4
@@ -76,8 +76,12 @@ new.features.train <- xgb.create.features(model = bst, agaricus.train$data)
 new.features.test <- xgb.create.features(model = bst, agaricus.test$data)
 
 # learning with new features
-new.dtrain <- xgb.DMatrix(data = new.features.train, label = agaricus.train$label)
-new.dtest <- xgb.DMatrix(data = new.features.test, label = agaricus.test$label)
+new.dtrain <- xgb.DMatrix(
+  data = new.features.train, label = agaricus.train$label, nthread = 2
+)
+new.dtest <- xgb.DMatrix(
+  data = new.features.test, label = agaricus.test$label, nthread = 2
+)
 watchlist <- list(train = new.dtrain)
 bst <- xgb.train(params = param, data = new.dtrain, nrounds = nrounds, nthread = 2)
 
diff --git a/R-package/man/xgb.cv.Rd b/R-package/man/xgb.cv.Rd
index 09f5091bd84f..8a962423de5e 100644
--- a/R-package/man/xgb.cv.Rd
+++ b/R-package/man/xgb.cv.Rd
@@ -158,9 +158,9 @@ Adapted from \url{https://en.wikipedia.org/wiki/Cross-validation_\%28statistics\
 }
 \examples{
 data(agaricus.train, package='xgboost')
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
 cv <- xgb.cv(data = dtrain, nrounds = 3, nthread = 2, nfold = 5, metrics = list("rmse","auc"),
-                  max_depth = 3, eta = 1, objective = "binary:logistic")
+             max_depth = 3, eta = 1, objective = "binary:logistic")
 print(cv)
 print(cv, verbose=TRUE)
 
diff --git a/R-package/man/xgb.plot.tree.Rd b/R-package/man/xgb.plot.tree.Rd
index 8fd7196afdba..d419eb76a02f 100644
--- a/R-package/man/xgb.plot.tree.Rd
+++ b/R-package/man/xgb.plot.tree.Rd
@@ -67,7 +67,7 @@ The "Yes" branches are marked by the "< split_value" label.
 The branches that also used for missing values are marked as bold
 (as in "carrying extra capacity").
 
-This function uses \href{http://www.graphviz.org/}{GraphViz} as a backend of DiagrammeR.
+This function uses \href{https://www.graphviz.org/}{GraphViz} as a backend of DiagrammeR.
 }
 \examples{
 data(agaricus.train, package='xgboost')
diff --git a/R-package/man/xgb.train.Rd b/R-package/man/xgb.train.Rd
index 5313bb15eea4..b2c9f9edc6d4 100644
--- a/R-package/man/xgb.train.Rd
+++ b/R-package/man/xgb.train.Rd
@@ -241,8 +241,8 @@ The following callbacks are automatically created when certain parameters are se
 data(agaricus.train, package='xgboost')
 data(agaricus.test, package='xgboost')
 
-dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label))
-dtest <- with(agaricus.test, xgb.DMatrix(data, label = label))
+dtrain <- with(agaricus.train, xgb.DMatrix(data, label = label, nthread = 2))
+dtest <- with(agaricus.test, xgb.DMatrix(data, label = label, nthread = 2))
 watchlist <- list(train = dtrain, eval = dtest)
 
 ## A simple xgb.train example:
diff --git a/R-package/src/Makevars.in b/R-package/src/Makevars.in
index 54f3acaa52bb..6902b6c1d927 100644
--- a/R-package/src/Makevars.in
+++ b/R-package/src/Makevars.in
@@ -3,7 +3,7 @@ PKGROOT=../../
 ENABLE_STD_THREAD=1
 # _*_ mode: Makefile; _*_
 
-CXX_STD = CXX14
+CXX_STD = CXX17
 
 XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
            -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\
@@ -23,7 +23,6 @@ PKG_LIBS = @OPENMP_CXXFLAGS@ @OPENMP_LIB@ @ENDIAN_FLAG@ @BACKTRACE_LIB@ -pthread
 OBJECTS= \
     ./xgboost_R.o \
     ./xgboost_custom.o \
-    ./xgboost_assert.o \
     ./init.o \
     $(PKGROOT)/src/metric/metric.o \
     $(PKGROOT)/src/metric/elementwise_metric.o \
diff --git a/R-package/src/Makevars.win b/R-package/src/Makevars.win
index c0815353203c..4a209258d458 100644
--- a/R-package/src/Makevars.win
+++ b/R-package/src/Makevars.win
@@ -3,7 +3,7 @@ PKGROOT=../../
 ENABLE_STD_THREAD=0
 # _*_ mode: Makefile; _*_
 
-CXX_STD = CXX14
+CXX_STD = CXX17
 
 XGB_RFLAGS = -DXGBOOST_STRICT_R_MODE=1 -DDMLC_LOG_BEFORE_THROW=0\
            -DDMLC_ENABLE_STD_THREAD=$(ENABLE_STD_THREAD) -DDMLC_DISABLE_STDIN=1\
@@ -23,7 +23,6 @@ PKG_LIBS = $(SHLIB_OPENMP_CXXFLAGS)  -DDMLC_CMAKE_LITTLE_ENDIAN=1  $(SHLIB_PTHRE
 OBJECTS= \
     ./xgboost_R.o \
     ./xgboost_custom.o \
-    ./xgboost_assert.o \
     ./init.o \
     $(PKGROOT)/src/metric/metric.o \
     $(PKGROOT)/src/metric/elementwise_metric.o \
diff --git a/R-package/src/xgboost_assert.c b/R-package/src/xgboost_assert.c
deleted file mode 100644
index 4706a039e8a6..000000000000
--- a/R-package/src/xgboost_assert.c
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright (c) 2014 by Contributors
-#include <stdio.h>
-#include <stdarg.h>
-#include <Rinternals.h>
-
-// implements error handling
-void XGBoostAssert_R(int exp, const char *fmt, ...) {
-  char buf[1024];
-  if (exp == 0) {
-    va_list args;
-    va_start(args, fmt);
-    vsprintf(buf, fmt, args);
-    va_end(args);
-    error("AssertError:%s\n", buf);
-  }
-}
-void XGBoostCheck_R(int exp, const char *fmt, ...) {
-  char buf[1024];
-  if (exp == 0) {
-    va_list args;
-    va_start(args, fmt);
-    vsprintf(buf, fmt, args);
-    va_end(args);
-    error("%s\n", buf);
-  }
-}
diff --git a/cmake/Python_version.in b/cmake/Python_version.in
index 67b48af46bf1..c55458ec2c28 100644
--- a/cmake/Python_version.in
+++ b/cmake/Python_version.in
@@ -1 +1 @@
-@xgboost_VERSION_MAJOR@.@xgboost_VERSION_MINOR@.@xgboost_VERSION_PATCH@-dev
\ No newline at end of file
+@xgboost_VERSION_MAJOR@.@xgboost_VERSION_MINOR@.@xgboost_VERSION_PATCH@
diff --git a/cmake/Utils.cmake b/cmake/Utils.cmake
index f28c1f2703e6..3a66735fe56f 100644
--- a/cmake/Utils.cmake
+++ b/cmake/Utils.cmake
@@ -178,17 +178,10 @@ function(xgboost_set_cuda_flags target)
       $<$<COMPILE_LANGUAGE:CUDA>:-Xcompiler=/utf-8>)
   endif (MSVC)
 
-  if (PLUGIN_RMM)
-    set_target_properties(${target} PROPERTIES
-      CUDA_STANDARD 17
-      CUDA_STANDARD_REQUIRED ON
-      CUDA_SEPARABLE_COMPILATION OFF)
-  else ()
-    set_target_properties(${target} PROPERTIES
-      CUDA_STANDARD 14
-      CUDA_STANDARD_REQUIRED ON
-      CUDA_SEPARABLE_COMPILATION OFF)
-  endif (PLUGIN_RMM)
+  set_target_properties(${target} PROPERTIES
+    CUDA_STANDARD 17
+    CUDA_STANDARD_REQUIRED ON
+    CUDA_SEPARABLE_COMPILATION OFF)
 endfunction(xgboost_set_cuda_flags)
 
 macro(xgboost_link_nccl target)
@@ -205,17 +198,10 @@ endmacro(xgboost_link_nccl)
 
 # compile options
 macro(xgboost_target_properties target)
-  if (PLUGIN_RMM)
-    set_target_properties(${target} PROPERTIES
-      CXX_STANDARD 17
-      CXX_STANDARD_REQUIRED ON
-      POSITION_INDEPENDENT_CODE ON)
-  else ()
-    set_target_properties(${target} PROPERTIES
-      CXX_STANDARD 14
-      CXX_STANDARD_REQUIRED ON
-      POSITION_INDEPENDENT_CODE ON)
-  endif (PLUGIN_RMM)
+  set_target_properties(${target} PROPERTIES
+    CXX_STANDARD 17
+    CXX_STANDARD_REQUIRED ON
+    POSITION_INDEPENDENT_CODE ON)
 
   if (HIDE_CXX_SYMBOLS)
     #-- Hide all C++ symbols
diff --git a/demo/c-api/CMakeLists.txt b/demo/c-api/CMakeLists.txt
index 25764c12ae46..9764267aa7c9 100644
--- a/demo/c-api/CMakeLists.txt
+++ b/demo/c-api/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.18)
 project(xgboost-c-examples)
 
 add_subdirectory(basic)
diff --git a/demo/c-api/external-memory/CMakeLists.txt b/demo/c-api/external-memory/CMakeLists.txt
index 0c21acb3ced8..5e68e9918013 100644
--- a/demo/c-api/external-memory/CMakeLists.txt
+++ b/demo/c-api/external-memory/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.18)
 project(external-memory-demo LANGUAGES C VERSION 0.0.1)
 
 find_package(xgboost REQUIRED)
diff --git a/demo/c-api/inference/CMakeLists.txt b/demo/c-api/inference/CMakeLists.txt
index 4d0f3cd6e52a..6aa8f1dd2dd5 100644
--- a/demo/c-api/inference/CMakeLists.txt
+++ b/demo/c-api/inference/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.18)
 project(inference-demo LANGUAGES C VERSION 0.0.1)
 find_package(xgboost REQUIRED)
 
diff --git a/dmlc-core b/dmlc-core
index dfd9365264a0..81db539486ce 160000
--- a/dmlc-core
+++ b/dmlc-core
@@ -1 +1 @@
-Subproject commit dfd9365264a060a5096734b7d892e1858b6d2722
+Subproject commit 81db539486ce6525b31b971545edffee2754aced
diff --git a/doc/contrib/release.rst b/doc/contrib/release.rst
index c457c6560a64..86dda38fee8b 100644
--- a/doc/contrib/release.rst
+++ b/doc/contrib/release.rst
@@ -4,7 +4,7 @@ XGBoost Release Policy
 =======================
 
 Versioning Policy
----------------------------
+-----------------
 
 Starting from XGBoost 1.0.0, each XGBoost release will be versioned as [MAJOR].[FEATURE].[MAINTENANCE]
 
@@ -34,6 +34,20 @@ Making a Release
 
    + The CRAN package is maintained by `Tong He <https://github.com/hetong007>`_ and `Jiaming Yuan <https://github.com/trivialfis>`__.
 
-     Before submitting a release, one should test the package on `R-hub <https://builder.r-hub.io/>`__ and `win-builder <https://win-builder.r-project.org/>`__ first.  Please note that the R-hub Windows instance doesn't have the exact same environment as the one hosted on win-builder.
-
    + The Maven package is maintained by `Nan Zhu <https://github.com/CodingCat>`_ and `Hyunsu Cho <https://github.com/hcho3>`_.
+
+
+R CRAN Package
+--------------
+Before submitting a release, one should test the package on `R-hub <https://builder.r-hub.io/>`__ and `win-builder <https://win-builder.r-project.org/>`__ first.  Please note that the R-hub Windows instance doesn't have the exact same environment as the one hosted on win-builder.
+
+According to the `CRAN policy <https://cran.r-project.org/web/packages/policies.html>`__:
+
+    If running a package uses multiple threads/cores it must never use more than two simultaneously: the check farm is a shared resource and will typically be running many checks simultaneously.
+
+We need to check the number of CPUs used in examples. Export ``_R_CHECK_EXAMPLE_TIMING_CPU_TO_ELAPSED_THRESHOLD_=2.5`` before running ``R CMD check --as-cran`` `[1] <#references>`__ and make sure the machine you are using has enough CPU cores to reveal any potential policy violation.
+
+References
+----------
+
+[1] https://stat.ethz.ch/pipermail/r-package-devel/2022q4/008610.html
diff --git a/doc/gpu/index.rst b/doc/gpu/index.rst
index 82309523f4cf..4187030c28fa 100644
--- a/doc/gpu/index.rst
+++ b/doc/gpu/index.rst
@@ -4,36 +4,21 @@ XGBoost GPU Support
 
 This page contains information about GPU algorithms supported in XGBoost.
 
-.. note:: CUDA 10.1, Compute Capability 3.5 required
-
-  The GPU algorithms in XGBoost require a graphics card with compute capability 3.5 or higher, with
-  CUDA toolkits 10.1 or later.
-  (See `this list <https://en.wikipedia.org/wiki/CUDA#GPUs_supported>`_ to look up compute capability of your GPU card.)
+.. note:: CUDA 11.0, Compute Capability 5.0 required (See `this list <https://en.wikipedia.org/wiki/CUDA#GPUs_supported>`_ to look up compute capability of your GPU card.)
 
 *********************************************
 CUDA Accelerated Tree Construction Algorithms
 *********************************************
-Tree construction (training) and prediction can be accelerated with CUDA-capable GPUs.
+
+Most of the algorithms in XGBoost including training, prediction and evaluation can be accelerated with CUDA-capable GPUs.
 
 Usage
 =====
-Specify the ``tree_method`` parameter as one of the following algorithms.
-
-Algorithms
-----------
-
-+-----------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
-| tree_method           | Description                                                                                                                                                           |
-+=======================+=======================================================================================================================================================================+
-| gpu_hist              | Equivalent to the XGBoost fast histogram algorithm. Much faster and uses considerably less memory. NOTE: May run very slowly on GPUs older than Pascal architecture.  |
-+-----------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+Specify the ``tree_method`` parameter as ``gpu_hist``. For details around the ``tree_method`` parameter, see :doc:`tree method </treemethod>`.
 
 Supported parameters
 --------------------
 
-.. |tick| unicode:: U+2714
-.. |cross| unicode:: U+2718
-
 GPU accelerated prediction is enabled by default for the above mentioned ``tree_method`` parameters but can be switched to CPU prediction by setting ``predictor`` to ``cpu_predictor``. This could be useful if you want to conserve GPU memory. Likewise when using CPU algorithms, GPU accelerated prediction can be enabled by setting ``predictor`` to ``gpu_predictor``.
 
 The device ordinal (which GPU to use if you have many of them) can be selected using the
@@ -69,128 +54,9 @@ See examples `here
 
 Multi-node Multi-GPU Training
 =============================
-XGBoost supports fully distributed GPU training using `Dask <https://dask.org/>`_. For
-getting started see our tutorial :doc:`/tutorials/dask` and worked examples `here
-<https://github.com/dmlc/xgboost/tree/master/demo/dask>`__, also Python documentation
-:ref:`dask_api` for complete reference.
-
-
-Objective functions
-===================
-Most of the objective functions implemented in XGBoost can be run on GPU.  Following table shows current support status.
-
-+----------------------+-------------+
-| Objectives           | GPU support |
-+----------------------+-------------+
-| reg:squarederror     | |tick|      |
-+----------------------+-------------+
-| reg:squaredlogerror  | |tick|      |
-+----------------------+-------------+
-| reg:logistic         | |tick|      |
-+----------------------+-------------+
-| reg:pseudohubererror | |tick|      |
-+----------------------+-------------+
-| binary:logistic      | |tick|      |
-+----------------------+-------------+
-| binary:logitraw      | |tick|      |
-+----------------------+-------------+
-| binary:hinge         | |tick|      |
-+----------------------+-------------+
-| count:poisson        | |tick|      |
-+----------------------+-------------+
-| reg:gamma            | |tick|      |
-+----------------------+-------------+
-| reg:tweedie          | |tick|      |
-+----------------------+-------------+
-| multi:softmax        | |tick|      |
-+----------------------+-------------+
-| multi:softprob       | |tick|      |
-+----------------------+-------------+
-| survival:cox         | |cross|     |
-+----------------------+-------------+
-| survival:aft         | |tick|      |
-+----------------------+-------------+
-| rank:pairwise        | |tick|      |
-+----------------------+-------------+
-| rank:ndcg            | |tick|      |
-+----------------------+-------------+
-| rank:map             | |tick|      |
-+----------------------+-------------+
-
-Objective will run on GPU if GPU updater (``gpu_hist``), otherwise they will run on CPU by
-default.  For unsupported objectives XGBoost will fall back to using CPU implementation by
-default.  Note that when using GPU ranking objective, the result is not deterministic due
-to the non-associative aspect of floating point summation.
-
-Metric functions
-===================
-Following table shows current support status for evaluation metrics on the GPU.
-
-+------------------------------+-------------+
-| Metric                       | GPU Support |
-+==============================+=============+
-| rmse                         | |tick|      |
-+------------------------------+-------------+
-| rmsle                        | |tick|      |
-+------------------------------+-------------+
-| mae                          | |tick|      |
-+------------------------------+-------------+
-| mape                         | |tick|      |
-+------------------------------+-------------+
-| mphe                         | |tick|      |
-+------------------------------+-------------+
-| logloss                      | |tick|      |
-+------------------------------+-------------+
-| error                        | |tick|      |
-+------------------------------+-------------+
-| merror                       | |tick|      |
-+------------------------------+-------------+
-| mlogloss                     | |tick|      |
-+------------------------------+-------------+
-| auc                          | |tick|      |
-+------------------------------+-------------+
-| aucpr                        | |tick|      |
-+------------------------------+-------------+
-| ndcg                         | |tick|      |
-+------------------------------+-------------+
-| map                          | |tick|      |
-+------------------------------+-------------+
-| poisson-nloglik              | |tick|      |
-+------------------------------+-------------+
-| gamma-nloglik                | |tick|      |
-+------------------------------+-------------+
-| cox-nloglik                  | |cross|     |
-+------------------------------+-------------+
-| aft-nloglik                  | |tick|      |
-+------------------------------+-------------+
-| interval-regression-accuracy | |tick|      |
-+------------------------------+-------------+
-| gamma-deviance               | |tick|      |
-+------------------------------+-------------+
-| tweedie-nloglik              | |tick|      |
-+------------------------------+-------------+
-
-Similar to objective functions, default device for metrics is selected based on tree
-updater and predictor (which is selected based on tree updater).
-
-Benchmarks
-==========
-You can run benchmarks on synthetic data for binary classification:
-
-.. code-block:: bash
-
-  python tests/benchmark/benchmark_tree.py --tree_method=gpu_hist
-  python tests/benchmark/benchmark_tree.py --tree_method=hist
-
-Training time on 1,000,000 rows x 50 columns of random data with 500 boosting iterations and 0.25/0.75 test/train split with AMD Ryzen 7 2700 8 core @3.20GHz and NVIDIA 1080ti yields the following results:
-
-+--------------+----------+
-| tree_method  | Time (s) |
-+==============+==========+
-| gpu_hist     | 12.57    |
-+--------------+----------+
-| hist         | 36.01    |
-+--------------+----------+
+
+XGBoost supports fully distributed GPU training using `Dask <https://dask.org/>`_, ``Spark`` and ``PySpark``. For getting started with Dask see our tutorial :doc:`/tutorials/dask` and worked examples `here <https://github.com/dmlc/xgboost/tree/master/demo/dask>`__, also Python documentation :ref:`dask_api` for complete reference. For usage with ``Spark`` using Scala see :doc:`/jvm/xgboost4j_spark_gpu_tutorial`. Lastly for distributed GPU training with ``PySpark``, see :doc:`/tutorials/spark_estimator`.
+
 
 Memory usage
 ============
@@ -202,7 +68,7 @@ The dataset itself is stored on device in a compressed ELLPACK format. The ELLPA
 
 Working memory is allocated inside the algorithm proportional to the number of rows to keep track of gradients, tree positions and other per row statistics. Memory is allocated for histogram bins proportional to the number of bins, number of features and nodes in the tree. For performance reasons we keep histograms in memory from previous nodes in the tree, when a certain threshold of memory usage is passed we stop doing this to conserve memory at some performance loss.
 
-If you are getting out-of-memory errors on a big dataset, try the or :py:class:`xgboost.DeviceQuantileDMatrix` or :doc:`external memory version </tutorials/external_memory>`.
+If you are getting out-of-memory errors on a big dataset, try the or :py:class:`xgboost.QuantileDMatrix` or :doc:`external memory version </tutorials/external_memory>`. Note that when ``external memory`` is used for GPU hist, it's best to employ gradient based sampling as well. Last but not least, ``inplace_predict`` can be preferred over ``predict`` when data is already on GPU. Both ``QuantileDMatrix`` and ``inplace_predict`` are automatically enabled if you are using the scikit-learn interface.
 
 Developer notes
 ===============
diff --git a/doc/parameter.rst b/doc/parameter.rst
index 837a7d1b0b7a..361847501357 100644
--- a/doc/parameter.rst
+++ b/doc/parameter.rst
@@ -44,8 +44,7 @@ General Parameters
 * ``validate_parameters`` [default to ``false``, except for Python, R and CLI interface]
 
   - When set to True, XGBoost will perform validation of input parameters to check whether
-    a parameter is used or not.  The feature is still experimental.  It's expected to have
-    some false positives.
+    a parameter is used or not.
 
 * ``nthread`` [default to maximum number of threads available if not set]
 
@@ -233,24 +232,21 @@ Parameters for Categorical Feature
 These parameters are only used for training with categorical data. See
 :doc:`/tutorials/categorical` for more information.
 
+.. note:: These parameters are experimental. ``exact`` tree method is not yet supported.
+
+
 * ``max_cat_to_onehot``
 
   .. versionadded:: 1.6.0
 
-  .. note:: This parameter is experimental. ``exact`` tree method is not yet supported.
-
   - A threshold for deciding whether XGBoost should use one-hot encoding based split for
     categorical data.  When number of categories is lesser than the threshold then one-hot
     encoding is chosen, otherwise the categories will be partitioned into children nodes.
-    Only relevant for regression and binary classification. Also, ``exact`` tree method is
-    not supported
 
 * ``max_cat_threshold``
 
   .. versionadded:: 1.7.0
 
-  .. note:: This parameter is experimental. ``exact`` tree method is not yet supported.
-
   - Maximum number of categories considered for each split. Used only by partition-based
     splits for preventing over-fitting.
 
diff --git a/doc/python/python_api.rst b/doc/python/python_api.rst
index a5ddd7831006..b27542a8becb 100644
--- a/doc/python/python_api.rst
+++ b/doc/python/python_api.rst
@@ -25,9 +25,6 @@ Core Data Structure
 .. autoclass:: xgboost.QuantileDMatrix
     :show-inheritance:
 
-.. autoclass:: xgboost.DeviceQuantileDMatrix
-    :show-inheritance:
-
 .. autoclass:: xgboost.Booster
     :members:
     :show-inheritance:
@@ -115,7 +112,7 @@ Dask API
     :inherited-members:
     :show-inheritance:
 
-.. autoclass:: xgboost.dask.DaskDeviceQuantileDMatrix
+.. autoclass:: xgboost.dask.DaskQuantileDMatrix
     :members:
     :inherited-members:
     :show-inheritance:
@@ -176,3 +173,13 @@ PySpark API
     :members:
     :inherited-members:
     :show-inheritance:
+
+.. autoclass:: xgboost.spark.SparkXGBRanker
+    :members:
+    :inherited-members:
+    :show-inheritance:
+
+.. autoclass:: xgboost.spark.SparkXGBRankerModel
+    :members:
+    :inherited-members:
+    :show-inheritance:
diff --git a/doc/tutorials/c_api_tutorial.rst b/doc/tutorials/c_api_tutorial.rst
index 5d4cb68cf7da..ad881bb5c68a 100644
--- a/doc/tutorials/c_api_tutorial.rst
+++ b/doc/tutorials/c_api_tutorial.rst
@@ -45,7 +45,7 @@ Use ``find_package()`` and ``target_link_libraries()`` in your application's CMa
 
 .. code-block:: cmake
 
-    cmake_minimum_required(VERSION 3.13)
+    cmake_minimum_required(VERSION 3.18)
     project(your_project_name LANGUAGES C CXX VERSION your_project_version)
     find_package(xgboost REQUIRED)
     add_executable(your_project_name /path/to/project_file.c)
diff --git a/doc/tutorials/categorical.rst b/doc/tutorials/categorical.rst
index 1c090801fae4..97877f23c190 100644
--- a/doc/tutorials/categorical.rst
+++ b/doc/tutorials/categorical.rst
@@ -138,11 +138,11 @@ Miscellaneous
 
 By default, XGBoost assumes input categories are integers starting from 0 till the number
 of categories :math:`[0, n\_categories)`. However, user might provide inputs with invalid
-values due to mistakes or missing values. It can be negative value, integer values that
-can not be accurately represented by 32-bit floating point, or values that are larger than
-actual number of unique categories.  During training this is validated but for prediction
-it's treated as the same as missing value for performance reasons.  Lastly, missing values
-are treated as the same as numerical features (using the learned split direction).
+values due to mistakes or missing values in training dataset. It can be negative value,
+integer values that can not be accurately represented by 32-bit floating point, or values
+that are larger than actual number of unique categories.  During training this is
+validated but for prediction it's treated as the same as not-chosen category for
+performance reasons.
 
 
 **********
diff --git a/doc/tutorials/dask.rst b/doc/tutorials/dask.rst
index e7fd85066646..fdc4dd20b11a 100644
--- a/doc/tutorials/dask.rst
+++ b/doc/tutorials/dask.rst
@@ -564,7 +564,7 @@ Here are some pratices on reducing memory usage with dask and xgboost.
   nice summary.
 
 - When using GPU input, like dataframe loaded by ``dask_cudf``, you can try
-  :py:class:`xgboost.dask.DaskDeviceQuantileDMatrix` as a drop in replacement for ``DaskDMatrix``
+  :py:class:`xgboost.dask.DaskQuantileDMatrix` as a drop in replacement for ``DaskDMatrix``
   to reduce overall memory usage.  See
   :ref:`sphx_glr_python_dask-examples_gpu_training.py` for an example.
 
diff --git a/doc/tutorials/spark_estimator.rst b/doc/tutorials/spark_estimator.rst
index acacada0b3eb..e0acc745433d 100644
--- a/doc/tutorials/spark_estimator.rst
+++ b/doc/tutorials/spark_estimator.rst
@@ -43,10 +43,10 @@ in spark estimator, and some parameters are replaced with pyspark specific param
 such as `weight_col`, `validation_indicator_col`, `use_gpu`, for details please see
 `SparkXGBRegressor` doc.
 
-The following code snippet shows how to train a spark xgboost regressor model,
-first we need to prepare a training dataset as a spark dataframe contains
-"label" column and "features" column(s), the "features" column(s) must be `pyspark.ml.linalg.Vector`
-type or spark array type or a list of feature column names.
+The following code snippet shows how to train a spark xgboost regressor model, first we
+need to prepare a training dataset as a spark dataframe contains "label" column and
+"features" column(s), the "features" column(s) must be ``pyspark.ml.linalg.Vector`` type
+or spark array type or a list of feature column names.
 
 
 .. code-block:: python
@@ -54,10 +54,10 @@ type or spark array type or a list of feature column names.
   xgb_regressor_model = xgb_regressor.fit(train_spark_dataframe)
 
 
-The following code snippet shows how to predict test data using a spark xgboost regressor model,
-first we need to prepare a test dataset as a spark dataframe contains
-"features" and "label" column, the "features" column must be `pyspark.ml.linalg.Vector`
-type or spark array type.
+The following code snippet shows how to predict test data using a spark xgboost regressor
+model, first we need to prepare a test dataset as a spark dataframe contains "features"
+and "label" column, the "features" column must be ``pyspark.ml.linalg.Vector`` type or
+spark array type.
 
 .. code-block:: python
 
@@ -83,17 +83,52 @@ generate result dataset with 3 new columns:
 XGBoost PySpark GPU support
 ***************************
 
-XGBoost PySpark supports GPU training and prediction. To enable GPU support, first you
-need to install the XGBoost and the `cuDF <https://docs.rapids.ai/api/cudf/stable/>`_
-package. Then you can set `use_gpu` parameter to `True`.
+XGBoost PySpark fully supports GPU acceleration. Users are not only able to enable
+efficient training but also utilize their GPUs for the whole PySpark pipeline including
+ETL and inference. In below sections, we will walk through an example of training on a
+PySpark standalone GPU cluster. To get started, first we need to install some additional
+packages, then we can set the `use_gpu` parameter to `True`.
 
-Below tutorial demonstrates how to train a model with XGBoost PySpark GPU on Spark
-standalone cluster.
+Prepare the necessary packages
+==============================
+
+Aside from the PySpark and XGBoost modules, we also need the `cuDF
+<https://docs.rapids.ai/api/cudf/stable/>`_ package for handling Spark dataframe. We
+recommend using either Conda or Virtualenv to manage python dependencies for PySpark
+jobs. Please refer to `How to Manage Python Dependencies in PySpark
+<https://www.databricks.com/blog/2020/12/22/how-to-manage-python-dependencies-in-pyspark.html>`_
+for more details on PySpark dependency management.
+
+In short, to create a Python environment that can be sent to a remote cluster using
+virtualenv and pip:
+
+.. code-block:: bash
+
+  python -m venv xgboost_env
+  source xgboost_env/bin/activate
+  pip install pyarrow pandas venv-pack xgboost
+  # https://rapids.ai/pip.html#install
+  pip install cudf-cu11 --extra-index-url=https://pypi.ngc.nvidia.com
+  venv-pack -o xgboost_env.tar.gz
+
+With Conda:
+
+.. code-block:: bash
+
+  conda create -y -n xgboost_env -c conda-forge conda-pack python=3.9
+  conda activate xgboost_env
+  # use conda when the supported version of xgboost (1.7) is released on conda-forge
+  pip install xgboost
+  conda install cudf pyarrow pandas -c rapids -c nvidia -c conda-forge
+  conda pack -f -o xgboost_env.tar.gz
 
 
 Write your PySpark application
 ==============================
 
+Below snippet is a small example for training xgboost model with PySpark. Notice that we are
+using a list of feature names and the additional parameter ``use_gpu``:
+
 .. code-block:: python
 
   from xgboost.spark import SparkXGBRegressor
@@ -127,26 +162,11 @@ Write your PySpark application
   predict_df = model.transform(test_df)
   predict_df.show()
 
-Prepare the necessary packages
-==============================
-
-We recommend using Conda or Virtualenv to manage python dependencies
-in PySpark. Please refer to
-`How to Manage Python Dependencies in PySpark <https://www.databricks.com/blog/2020/12/22/how-to-manage-python-dependencies-in-pyspark.html>`_.
-
-.. code-block:: bash
-
-  conda create -y -n xgboost-env -c conda-forge conda-pack python=3.9
-  conda activate xgboost-env
-  pip install xgboost
-  conda install cudf -c rapids -c nvidia -c conda-forge
-  conda pack -f -o xgboost-env.tar.gz
-
 
 Submit the PySpark application
 ==============================
 
-Assuming you have configured your Spark cluster with GPU support, if not yet, please
+Assuming you have configured your Spark cluster with GPU support. Otherwise, please
 refer to `spark standalone configuration with GPU support <https://nvidia.github.io/spark-rapids/docs/get-started/getting-started-on-prem.html#spark-standalone-cluster>`_.
 
 .. code-block:: bash
@@ -158,10 +178,13 @@ refer to `spark standalone configuration with GPU support <https://nvidia.github
     --master spark://<master-ip>:7077 \
     --conf spark.executor.resource.gpu.amount=1 \
     --conf spark.task.resource.gpu.amount=1 \
-    --archives xgboost-env.tar.gz#environment \
+    --archives xgboost_env.tar.gz#environment \
     xgboost_app.py
 
 
+The submit command sends the Python environment created by pip or conda along with the
+specification of GPU allocation. We will revisit this command later on.
+
 Model Persistence
 =================
 
@@ -186,26 +209,27 @@ To export the underlying booster model used by XGBoost:
   # the same booster object returned by xgboost.train
   booster: xgb.Booster = model.get_booster()
   booster.predict(...)
-  booster.save_model("model.json")
+  booster.save_model("model.json") # or model.ubj, depending on your choice of format.
 
-This booster is shared by other Python interfaces and can be used by other language
-bindings like the C and R packages. Lastly, one can extract a booster file directly from
-saved spark estimator without going through the getter:
+This booster is not only shared by other Python interfaces but also used by all the
+XGBoost bindings including the C, Java, and the R package. Lastly, one can extract the
+booster file directly from a saved spark estimator without going through the getter:
 
 .. code-block:: python
 
   import xgboost as xgb
   bst = xgb.Booster()
+  # Loading the model saved in previous snippet
   bst.load_model("/tmp/xgboost-pyspark-model/model/part-00000")
 
-Accelerate the whole pipeline of xgboost pyspark
-================================================
 
-With `RAPIDS Accelerator for Apache Spark <https://nvidia.github.io/spark-rapids/>`_,
-you can accelerate the whole pipeline (ETL, Train, Transform) for xgboost pyspark
-without any code change by leveraging GPU.
+Accelerate the whole pipeline for xgboost pyspark
+=================================================
 
-Below is a simple example submit command for enabling GPU acceleration:
+With `RAPIDS Accelerator for Apache Spark <https://nvidia.github.io/spark-rapids/>`_, you
+can leverage GPUs to accelerate the whole pipeline (ETL, Train, Transform) for xgboost
+pyspark without any Python code change. An example submit command is shown below with
+additional spark configurations and dependencies:
 
 .. code-block:: bash
 
@@ -219,8 +243,9 @@ Below is a simple example submit command for enabling GPU acceleration:
     --packages com.nvidia:rapids-4-spark_2.12:22.08.0 \
     --conf spark.plugins=com.nvidia.spark.SQLPlugin \
     --conf spark.sql.execution.arrow.maxRecordsPerBatch=1000000 \
-    --archives xgboost-env.tar.gz#environment \
+    --archives xgboost_env.tar.gz#environment \
     xgboost_app.py
 
-When rapids plugin is enabled, both of the JVM rapids plugin and the cuDF Python are
-required for the acceleration.
+When rapids plugin is enabled, both of the JVM rapids plugin and the cuDF Python package
+are required. More configuration options can be found in the RAPIDS link above along with
+details on the plugin.
diff --git a/gputreeshap b/gputreeshap
index acb5be3c17e9..787259b412c1 160000
--- a/gputreeshap
+++ b/gputreeshap
@@ -1 +1 @@
-Subproject commit acb5be3c17e9adae34ac0b176da6ea8e197cb17e
+Subproject commit 787259b412c18ab8d5f24bf2b8bd6a59ff8208f3
diff --git a/include/xgboost/c_api.h b/include/xgboost/c_api.h
index 2daa4203878b..0d91c56df5c5 100644
--- a/include/xgboost/c_api.h
+++ b/include/xgboost/c_api.h
@@ -984,6 +984,31 @@ XGB_DLL int XGBoosterPredict(BoosterHandle handle,
                              bst_ulong *out_len,
                              const float **out_result);
 
+/*!
+ * \brief make prediction based on dmat (deprecated, use `XGBoosterPredictFromDMatrix` instead)
+ * \param handle handle
+ * \param dmat data matrix
+ * \param option_mask bit-mask of options taken in prediction, possible values
+ *          0:normal prediction
+ *          1:output margin instead of transformed value
+ *          2:output leaf index of trees instead of leaf value, note leaf index is unique per tree
+ *          4:output feature contributions to individual predictions
+ * \param out_len used to store length of returning result
+ * \param out_result used to set a pointer to array
+ * \return 0 when success, -1 when failure happens
+*/
+//TODO: Fix documentation above
+XGB_DLL int XGBoosterInplacePredict(BoosterHandle handle,
+                                    const float *data,
+                                    size_t num_rows,
+                                    size_t num_features,
+                                    DMatrixHandle d_matrix_handle,
+                                    float missing,
+                                    int option_mask,
+                                    int ntree_limit,
+                                    const bst_ulong **len,
+                                    const float **out_result);
+
 /*!
  * \brief Make prediction from DMatrix, replacing \ref XGBoosterPredict.
  *
diff --git a/include/xgboost/collective/socket.h b/include/xgboost/collective/socket.h
index e058e58a843f..33d14fe8ca19 100644
--- a/include/xgboost/collective/socket.h
+++ b/include/xgboost/collective/socket.h
@@ -287,11 +287,22 @@ class TCPSocket {
 #elif defined(__APPLE__)
     return domain_;
 #elif defined(__unix__)
+#ifndef __PASE__
     std::int32_t domain;
     socklen_t len = sizeof(domain);
     xgboost_CHECK_SYS_CALL(
         getsockopt(handle_, SOL_SOCKET, SO_DOMAIN, reinterpret_cast<char *>(&domain), &len), 0);
     return ret_iafamily(domain);
+#else
+    struct sockaddr sa;
+    socklen_t sizeofsa = sizeof(sa);
+    xgboost_CHECK_SYS_CALL(
+      getsockname(handle_, &sa, &sizeofsa), 0);
+    if (sizeofsa < sizeof(uchar_t)*2) {
+      return ret_iafamily(AF_INET);
+    }
+    return ret_iafamily(sa.sa_family);
+#endif   // __PASE__
 #else
     LOG(FATAL) << "Unknown platform.";
     return ret_iafamily(AF_INET);
diff --git a/include/xgboost/version_config.h b/include/xgboost/version_config.h
index b8b4517f0468..22fb2ad5027d 100644
--- a/include/xgboost/version_config.h
+++ b/include/xgboost/version_config.h
@@ -6,6 +6,6 @@
 
 #define XGBOOST_VER_MAJOR 1
 #define XGBOOST_VER_MINOR 7
-#define XGBOOST_VER_PATCH 0
+#define XGBOOST_VER_PATCH 5
 
 #endif  // XGBOOST_VERSION_CONFIG_H_
diff --git a/jvm-packages/create_jni.py b/jvm-packages/create_jni.py
index 18908fc1c0d5..835d799612d7 100755
--- a/jvm-packages/create_jni.py
+++ b/jvm-packages/create_jni.py
@@ -15,7 +15,7 @@
 
 
 CONFIG = {
-    "USE_OPENMP": "ON",
+    "USE_OPENMP": "OFF",
     "USE_HDFS": "OFF",
     "USE_AZURE": "OFF",
     "USE_S3": "OFF",
@@ -118,7 +118,7 @@ def normpath(path):
             lib_dir = os.path.join(os.pardir, 'lib')
             if os.path.exists(lib_dir):
                 shutil.rmtree(lib_dir)
-            run("cmake .. " + " ".join(args) + maybe_generator)
+            run("cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo .. " + " ".join(args) + maybe_generator)
             run("cmake --build . --config Release" + maybe_parallel_build)
 
         with cd("demo/CLI/regression"):
diff --git a/jvm-packages/pom.xml b/jvm-packages/pom.xml
index e07b987830a5..0086614f0408 100644
--- a/jvm-packages/pom.xml
+++ b/jvm-packages/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>ml.dmlc</groupId>
     <artifactId>xgboost-jvm_2.12</artifactId>
-    <version>1.7.0-SNAPSHOT</version>
+    <version>1.7.5-sovrn-no-openmp-cpucache</version>
     <packaging>pom</packaging>
     <name>XGBoost JVM Package</name>
     <description>JVM Package for XGBoost</description>
diff --git a/jvm-packages/xgboost4j-example/pom.xml b/jvm-packages/xgboost4j-example/pom.xml
index a6857364dcb2..4f6885506e01 100644
--- a/jvm-packages/xgboost4j-example/pom.xml
+++ b/jvm-packages/xgboost4j-example/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j-example_2.12</artifactId>
-    <version>1.7.0-SNAPSHOT</version>
+    <version>1.7.5-sovrn-no-openmp-cpucache</version>
     <packaging>jar</packaging>
     <build>
         <plugins>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-spark_${scala.binary.version}</artifactId>
-            <version>1.7.0-SNAPSHOT</version>
+            <version>1.7.5</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
@@ -37,7 +37,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-flink_${scala.binary.version}</artifactId>
-            <version>1.7.0-SNAPSHOT</version>
+            <version>1.7.5</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
diff --git a/jvm-packages/xgboost4j-flink/pom.xml b/jvm-packages/xgboost4j-flink/pom.xml
index f6ba1747d3ef..0a9a278f08ef 100644
--- a/jvm-packages/xgboost4j-flink/pom.xml
+++ b/jvm-packages/xgboost4j-flink/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j-flink_2.12</artifactId>
-    <version>1.7.0-SNAPSHOT</version>
+    <version>1.7.5-sovrn-no-openmp-cpucache</version>
     <build>
         <plugins>
             <plugin>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.7.0-SNAPSHOT</version>
+            <version>1.7.5-sovrn-no-openmp-cpucache</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
diff --git a/jvm-packages/xgboost4j-gpu/pom.xml b/jvm-packages/xgboost4j-gpu/pom.xml
index 6e4651a4c39f..45fa5f563f70 100644
--- a/jvm-packages/xgboost4j-gpu/pom.xml
+++ b/jvm-packages/xgboost4j-gpu/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j-gpu_2.12</artifactId>
-    <version>1.7.0-SNAPSHOT</version>
+    <version>1.7.5-sovrn-no-openmp-cpucache</version>
     <packaging>jar</packaging>
 
     <dependencies>
diff --git a/jvm-packages/xgboost4j-gpu/src/native/xgboost4j-gpu.cu b/jvm-packages/xgboost4j-gpu/src/native/xgboost4j-gpu.cu
index 4ecf8b0f1da1..bf3f6a0db316 100644
--- a/jvm-packages/xgboost4j-gpu/src/native/xgboost4j-gpu.cu
+++ b/jvm-packages/xgboost4j-gpu/src/native/xgboost4j-gpu.cu
@@ -1,7 +1,7 @@
 #include <jni.h>
-#include <thrust/system/cuda/experimental/pinned_allocator.h>
 
 #include "../../../../src/common/device_helpers.cuh"
+#include "../../../../src/common/cuda_pinned_allocator.h"
 #include "../../../../src/data/array_interface.h"
 #include "jvm_utils.h"
 #include <xgboost/c_api.h>
@@ -131,7 +131,7 @@ class DataIteratorProxy {
   bool cache_on_host_{true}; // TODO(Bobby): Make this optional.
 
   template <typename T>
-  using Alloc = thrust::system::cuda::experimental::pinned_allocator<T>;
+  using Alloc = xgboost::common::cuda::pinned_allocator<T>;
   template <typename U>
   using HostVector = std::vector<U, Alloc<U>>;
 
diff --git a/jvm-packages/xgboost4j-spark-gpu/pom.xml b/jvm-packages/xgboost4j-spark-gpu/pom.xml
index bac014776f20..f032d64bad0a 100644
--- a/jvm-packages/xgboost4j-spark-gpu/pom.xml
+++ b/jvm-packages/xgboost4j-spark-gpu/pom.xml
@@ -6,7 +6,7 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j-spark-gpu_2.12</artifactId>
     <build>
@@ -24,7 +24,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-gpu_${scala.binary.version}</artifactId>
-            <version>1.7.0-SNAPSHOT</version>
+            <version>1.7.5-sovrn-2</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
diff --git a/jvm-packages/xgboost4j-spark/pom.xml b/jvm-packages/xgboost4j-spark/pom.xml
index 5e5e0becb189..ce2d60846848 100644
--- a/jvm-packages/xgboost4j-spark/pom.xml
+++ b/jvm-packages/xgboost4j-spark/pom.xml
@@ -6,7 +6,7 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j-spark_2.12</artifactId>
     <build>
@@ -24,7 +24,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.7.0-SNAPSHOT</version>
+            <version>1.7.5-sovrn-no-openmp-cpucache</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
diff --git a/jvm-packages/xgboost4j-tester/get_iris.py b/jvm-packages/xgboost4j-tester/get_iris.py
index f234bb95e198..728c149b0260 100644
--- a/jvm-packages/xgboost4j-tester/get_iris.py
+++ b/jvm-packages/xgboost4j-tester/get_iris.py
@@ -1,9 +1,9 @@
-from sklearn.datasets import load_iris
 import numpy as np
 import pandas
+from sklearn.datasets import load_iris
 
 X, y = load_iris(return_X_y=True)
-y = y.astype(np.int)
+y = y.astype(np.int32)
 df = pandas.DataFrame(data=X, columns=['sepal length', 'sepal width', 'petal length', 'petal width'])
 class_id_to_name = {0:'Iris-setosa', 1:'Iris-versicolor', 2:'Iris-virginica'}
 df['class'] = np.vectorize(class_id_to_name.get)(y)
diff --git a/jvm-packages/xgboost4j/pom.xml b/jvm-packages/xgboost4j/pom.xml
index 9551ffcd97a5..673e0e7f82be 100644
--- a/jvm-packages/xgboost4j/pom.xml
+++ b/jvm-packages/xgboost4j/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.5-sovrn-no-openmp-cpucache</version>
     </parent>
     <artifactId>xgboost4j_2.12</artifactId>
-    <version>1.7.0-SNAPSHOT</version>
+    <version>1.7.5-sovrn-no-openmp-cpucache</version>
     <packaging>jar</packaging>
 
     <dependencies>
@@ -81,7 +81,7 @@
                           <goal>exec</goal>
                       </goals>
                       <configuration>
-                          <executable>python</executable>
+                          <executable>python3</executable>
                           <arguments>
                             <argument>create_jni.py</argument>
                             <argument>--log-capi-invocation</argument>
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Booster.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Booster.java
index ed1a3f5c9f92..4173250a8dc8 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Booster.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Booster.java
@@ -315,6 +315,160 @@ private synchronized float[][] predict(DMatrix data,
     }
     return predicts;
   }
+  // TODO - ANYTHING
+  /**
+   * Perform thread-safe prediction. Calls
+   * <code>inplace_predict(data, num_rows, num_features, Float.NaN, false, 0, false, false)</code>.
+   *
+   * @param data           Flattened input matrix of features for prediction
+   * @param num_rows       The number of preditions to make (count of input matrix rows)
+   * @param num_features   The number of features in the model (count of input matrix columns)
+   *
+   * @return predict       Result matrix
+   *
+   * @see #inplace_predict(float[] data, int num_rows, int num_features, float missing,
+   *                       boolean outputMargin, int treeLimit, boolean predLeaf,
+   *                       boolean predContribs)
+   */
+  public float[][] inplace_predict(float[] data,
+                                   int num_rows,
+                                   int num_features) throws XGBoostError {
+    return this.inplace_predict(data, num_rows, num_features,
+                Float.NaN, false, 0, false, false);
+  }
+
+  /**
+   * Perform thread-safe prediction. Calls
+   * <code>inplace_predict(data, num_rows, num_features, missing, false, 0, false, false)</code>.
+   *
+   * @param data           Flattened input matrix of features for prediction
+   * @param num_rows       The number of preditions to make (count of input matrix rows)
+   * @param num_features   The number of features in the model (count of input matrix columns)
+   * @param missing        Value indicating missing element in the <code>data</code> input matrix
+   *
+   * @return predict       Result matrix
+   *
+   * @see #inplace_predict(float[] data, int num_rows, int num_features, float missing,
+   *                       boolean outputMargin, int treeLimit, boolean predLeaf,
+   *                       boolean predContribs)
+   */
+  public float[][] inplace_predict(float[] data,
+                                   int num_rows,
+                                   int num_features,
+                                   float missing) throws XGBoostError {
+    return this.inplace_predict(data, num_rows, num_features,
+                missing, false, 0, false, false);
+  }
+
+  /**
+   * Perform thread-safe prediction. Calls
+   * <code>inplace_predict(data, num_rows, num_features, missing,
+   *                       outputMargin, 0, false, false)</code>.
+   *
+   * @param data           Flattened input matrix of features for prediction
+   * @param num_rows       The number of preditions to make (count of input matrix rows)
+   * @param num_features   The number of features in the model (count of input matrix columns)
+   * @param missing        Value indicating missing element in the <code>data</code> input matrix
+   * @param outputMargin   Whether to only predict margin value instead of transformed prediction
+   *
+   * @return predict       Result matrix
+   *
+   * @see #inplace_predict(float[] data, int num_rows, int num_features, float missing,
+   *                       boolean outputMargin, int treeLimit, boolean predLeaf,
+   *                       boolean predContribs)
+   */
+
+  public float[][] inplace_predict(float[] data,
+                                   int num_rows,
+                                   int num_features,
+                                   float missing,
+                                   boolean outputMargin) throws XGBoostError {
+    return this.inplace_predict(data, num_rows, num_features, missing,
+                       outputMargin, 0, false, false);
+  }
+
+  /**
+   * Perform thread-safe prediction. Calls
+   * <code>inplace_predict(data, num_rows, num_features, missing,
+   *                       outputMargin, treeLimit, false, false)</code>.
+   *
+   * @param data           Flattened input matrix of features for prediction
+   * @param num_rows       The number of preditions to make (count of input matrix rows)
+   * @param num_features   The number of features in the model (count of input matrix columns)
+   * @param missing        Value indicating missing element in the <code>data</code> input matrix
+   * @param outputMargin   Whether to only predict margin value instead of transformed prediction
+   * @param treeLimit      limit number of trees, 0 means all trees.
+   *
+   * @return predict       Result matrix
+   *
+   * @see #inplace_predict(float[] data, int num_rows, int num_features, float missing,
+   *                       boolean outputMargin, int treeLimit, boolean predLeaf,
+   *                       boolean predContribs)
+   */
+  public float[][] inplace_predict(float[] data,
+                                   int num_rows,
+                                   int num_features,
+                                   float missing,
+                                   boolean outputMargin,
+                                   int treeLimit) throws XGBoostError {
+    return this.inplace_predict(data, num_rows, num_features, missing,
+                                outputMargin, treeLimit, false, false);
+  }
+
+  /**
+   * Perform thread-safe prediction.
+   *
+   * @param data           Flattened input matrix of features for prediction
+   * @param num_rows       The number of preditions to make (count of input matrix rows)
+   * @param num_features   The number of features in the model (count of input matrix columns)
+   * @param d_matrix_h     The handle for a dmatrix
+   * @param missing        Value indicating missing element in the <code>data</code> input matrix
+   * @param outputMargin   Whether to only predict margin value instead of transformed prediction
+   * @param treeLimit      limit number of trees, 0 means all trees.
+   * @param predLeaf       prediction minimum to keep leafs
+   * @param predContribs   prediction feature contributions
+   *
+   * @return predict       Result matrix
+   */
+  public float[][] inplace_predict(float[] data,
+                                   int num_rows,
+                                   int num_features,
+                                   float missing,
+                                   boolean outputMargin,
+                                   int treeLimit,
+                                   boolean predLeaf,
+                                   boolean predContribs) throws XGBoostError {
+    int optionMask = 0;
+    if (outputMargin) {
+      optionMask |= 1;
+    }
+    if (predLeaf) {
+      optionMask = 2;
+    }
+    if (predContribs) {
+      optionMask = 4;
+    }
+    float[][] rawPredicts = new float[1][];
+    // The DMatrix in this JNI call is completely unused, and creating one actually causes
+    // performance problems. So we will just pass a 0L handle
+    XGBoostJNI.checkCall(XGBoostJNI.XGBoosterInplacePredict(handle, data, num_rows, num_features,
+        0L, missing, optionMask, treeLimit, rawPredicts));
+    // pass missing and treelimit here?
+
+    // System.out.println("Booster.inplace_predict rawPredicts[0].length = " +
+    //    rawPredicts[0].length);
+
+    int row = num_rows;
+    int col = rawPredicts[0].length / row;
+    float[][] predicts = new float[row][col];
+    int r, c;
+    for (int i = 0; i < rawPredicts[0].length; i++) {
+      r = i / col;
+      c = i % col;
+      predicts[r][c] = rawPredicts[0][i];
+    }
+    return predicts;
+  }
 
   /**
    * Predict leaf indices given the data
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XGBoostJNI.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XGBoostJNI.java
index afe576598956..49921983d461 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XGBoostJNI.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XGBoostJNI.java
@@ -113,6 +113,10 @@ public final static native int XGBoosterEvalOneIter(long handle, int iter, long[
 
   public final static native int XGBoosterPredict(long handle, long dmat, int option_mask,
                                                   int ntree_limit, float[][] predicts);
+  // TODO - anything
+  public final static native int XGBoosterInplacePredict(long handle, float[] data, int num_rows, int num_features, long d_matrix_handle,
+                                                         float missing, int option_mask, int ntree_limit,
+                                                         float[][] predicts);
 
   public final static native int XGBoosterLoadModel(long handle, String fname);
 
diff --git a/jvm-packages/xgboost4j/src/native/xgboost4j.cpp b/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
index 749fa5b40cdb..79932678cf5a 100644
--- a/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
+++ b/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
@@ -608,6 +608,34 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterPredict
   return ret;
 }
 
+// TODO - ANYTHING
+/*
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
+ * Method:    XGBoosterInplacePredict
+ * Signature: (J[FIII[[F)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterInplacePredict
+  (JNIEnv *jenv, jclass jcls, jlong jhandle, jfloatArray jdata, jint num_rows, jint num_features, jlong d_matrix_handle,
+                                             jfloat missing, jint option_mask, jint treeLimit, jobjectArray jout) {
+  BoosterHandle handle = (BoosterHandle) jhandle;
+  DMatrixHandle dmat = (DMatrixHandle) d_matrix_handle;
+  jfloat* data = jenv->GetFloatArrayElements(jdata, 0);
+  const bst_ulong *len;
+  float *result;
+  int ret = XGBoosterInplacePredict(handle, data, num_rows, num_features, dmat, missing, option_mask, treeLimit,
+            &len, (const float **) &result);
+  JVM_CHECK_CALL(ret);
+  jenv->ReleaseFloatArrayElements(jdata, data, 0);
+  if (*len) {
+//    printf("JNI XGBoosterInplacePredict len = %u\n", *len);
+    jsize jlen = (jsize) *len;
+    jfloatArray jarray = jenv->NewFloatArray(jlen);
+    jenv->SetFloatArrayRegion(jarray, 0, jlen, (jfloat *) result);
+    jenv->SetObjectArrayElement(jout, 0, jarray);
+  }
+  return ret;
+}
+
 /*
  * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModel
diff --git a/jvm-packages/xgboost4j/src/native/xgboost4j.h b/jvm-packages/xgboost4j/src/native/xgboost4j.h
index 5afe92b524ab..dc8c9f5ee56b 100644
--- a/jvm-packages/xgboost4j/src/native/xgboost4j.h
+++ b/jvm-packages/xgboost4j/src/native/xgboost4j.h
@@ -183,6 +183,13 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterEvalOneIt
 JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterPredict
   (JNIEnv *, jclass, jlong, jlong, jint, jint, jobjectArray);
 
+/*
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
+ * Method:    XGBoosterInplacePredict
+ * Signature: (J[FIII[[F)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterInplacePredict
+  (JNIEnv *, jclass, jlong, jfloatArray, jint, jint, jlong, jfloat, jint, jint, jobjectArray);
 /*
  * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModel
diff --git a/jvm-packages/xgboost4j/src/test/java/ml/dmlc/xgboost4j/java/BoosterImplTest.java b/jvm-packages/xgboost4j/src/test/java/ml/dmlc/xgboost4j/java/BoosterImplTest.java
index cce1254d0f87..4041db945a70 100644
--- a/jvm-packages/xgboost4j/src/test/java/ml/dmlc/xgboost4j/java/BoosterImplTest.java
+++ b/jvm-packages/xgboost4j/src/test/java/ml/dmlc/xgboost4j/java/BoosterImplTest.java
@@ -24,6 +24,166 @@
 import junit.framework.TestCase;
 import org.junit.Test;
 
+import java.util.Random;
+import java.io.PrintStream;
+import java.util.*;
+import java.util.concurrent.*;
+
+//
+// Utility class for comparing array contents
+//
+class ArrayComparator {
+  public static boolean compare(float[][] one, float[][] two) {
+
+    // Test that both arrays are the same size in the first dimension
+    if (one.length != two.length) {
+      System.err.println("Array first dimensions are not identical in size");
+      return false;
+    }
+
+    // Test that both arrays are the same size in the second dimension
+    if (one[0].length != two[0].length) {
+      System.err.println("Array second dimensions are not identical in size");
+      return false;
+    }
+
+    // Test that all the array elements are identical
+    for (int i=0; i<one.length; i++) {
+      for (int j=0; j<one[i].length; j++) {
+        if (one[i][j] != two[i][j]) {
+          System.err.println("Array elements [" + i + "][" + j + "] are not identical");
+          System.err.println(one[i][j] + " != " + two[i][j]);
+          return false;
+        }
+      }
+    }
+
+    return true;
+  }
+}
+
+//
+// Utility class for printing out array contents
+//
+class ArrayPrinter {
+  PrintStream stream;
+
+  public ArrayPrinter() {
+    stream = System.out;
+  }
+  public ArrayPrinter(PrintStream stream) {
+    this.stream = stream;
+  }
+
+  public void print(String name, float[][] a) {
+    stream.print(name + " = [");
+
+    for (int i=0; i < a.length-1; i++) {
+      stream.print(a[i][0] + ", ");
+    }
+    stream.println(a[a.length-1][0] + "]");
+  }
+}
+
+//
+// Performs a series of single-vector in-place predictions in a dedicated thread
+//
+class InplacePredictThread extends Thread {
+
+  int thread_num;
+  boolean success = true;
+  float[][] testX;
+  int test_rows;
+  int features;
+  float[][] true_predicts;
+  Booster booster;
+  Random rng = new Random();
+  int n_preds = 100;
+
+  public InplacePredictThread(int n, Booster booster, float[][] testX, int test_rows, int features, float[][] true_predicts) {
+    this.thread_num = n;
+    this.booster = booster;
+    this.testX = testX;
+    this.test_rows = test_rows;
+    this.features = features;
+    this.true_predicts = true_predicts;
+  }
+
+  @Override
+  public void run() {
+//    System.err.println("Thread #" + thread_num + " started.");
+
+    try {
+      // Perform n_preds number of single-vector predictions
+      for (int i=0; i<n_preds; i++) {
+        // Randomly generate int in range 0 <= r < test_rows
+        int r = this.rng.nextInt(this.test_rows);
+
+        // In-place predict a single random row
+        float[][] predictions = booster.inplace_predict(this.testX[r], 1, this.features);
+
+        // Confirm results as expected
+        if (predictions[0][0] != this.true_predicts[r][0]) {
+//          System.err.println("Error in thread #" + this.thread_num);
+          success = false;
+          return;  // bail at the first error.
+        }
+      }
+    } catch (XGBoostError e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  public boolean isSuccess() {
+    return success;
+  }
+}
+
+class InplacePredictionTask implements Callable<Boolean> {
+  int task_num;
+  float[][] testX;
+  int test_rows;
+  int features;
+  float[][] true_predicts;
+  Booster booster;
+  Random rng = new Random();
+  int n_preds = 100;
+
+  public InplacePredictionTask(int n, Booster booster, float[][] testX, int test_rows, int features, float[][] true_predicts) {
+    this.task_num = n;
+    this.booster = booster;
+    this.testX = testX;
+    this.test_rows = test_rows;
+    this.features = features;
+    this.true_predicts = true_predicts;
+  }
+
+  @Override
+  public Boolean call() throws Exception {
+//    System.err.println("Task #" + task_num + " started.");
+
+    // Perform n_preds number of single-vector predictions
+    for (int i=0; i<n_preds; i++) {
+      // Randomly generate int in range 0 <= r < test_rows
+      int r = this.rng.nextInt(this.test_rows);
+
+      // In-place predict a single random row
+      float[][] predictions = booster.inplace_predict(this.testX[r], 1, this.features);
+
+      // Confirm results as expected
+      if (predictions[0][0] != this.true_predicts[r][0]) {
+          System.err.println("Error in task #" + this.task_num);
+        return false;  // bail at the first error.
+      }
+    }
+
+//    System.err.println("Task #" + task_num + " finished.");
+
+    // No errors found
+    return true;
+  }
+}
+
 /**
  * test cases for Booster
  *
@@ -101,6 +261,120 @@ public void testBoosterBasic() throws XGBoostError, IOException {
     //error must be less than 0.1
     TestCase.assertTrue(eval.eval(predicts, testMat) < 0.1f);
   }
+  @Test
+  public void testBoosterInplacePredict() throws  XGBoostError, IOException {
+
+//    System.out.println("=-=-=-=-=- testBoosterInplacePredict 2 =-=-=-=-=");
+
+    Random rng = new Random();
+
+    // Data generation
+
+    // Randomly generate raining set
+    int train_rows = 1000;
+    int features = 10;
+    int train_size = train_rows * features;
+    float[] trainX = new float[train_size];
+    float[] trainy = new float[train_rows];
+
+    for (int i=0; i<train_size; i++) {
+      trainX[i] = rng.nextFloat();
+    }
+    for (int i=0; i<train_rows; i++) {
+      trainy[i] = rng.nextFloat();
+    }
+
+    DMatrix trainMat = new DMatrix(trainX, train_rows, features, Float.NaN);
+    trainMat.setLabel(trainy);
+
+    // Randomly generate testing set
+    int test_rows = 10;
+    int test_size = test_rows * features;
+    float[] testX = new float[test_size];
+    float[] testy = new float[test_rows];
+
+    for (int i=0; i<test_size; i++) {
+      testX[i] = rng.nextFloat();
+    }
+    for (int i=0; i<test_rows; i++) {
+      testy[i] = rng.nextFloat();
+    }
+
+    DMatrix testMat = new DMatrix(testX, test_rows, features, Float.NaN);
+    testMat.setLabel(testy);
+
+    // Training
+
+    // Set parameters
+    Map<String, Object> params = new HashMap<String, Object>() {
+      {
+        put("eta", 1.0);
+        put("max_depth", 2);
+        put("silent", 1);
+        put("tree_method", "hist");
+      }
+    };
+
+    Map<String, DMatrix> watches = new HashMap<String, DMatrix>() {
+      {
+        put("train", trainMat);
+        put("test", testMat);
+      }
+    };
+
+    Booster booster = XGBoost.train(trainMat, params, 10, watches, null, null);
+
+
+    // Prediction
+
+    // standard prediction
+    float[][] predicts = booster.predict(testMat);
+
+    // inplace prediction
+    float[][] inplace_predicts = booster.inplace_predict(testX, test_rows, features);
+
+    // Confirm that the two prediction results are identical
+    TestCase.assertTrue(ArrayComparator.compare(predicts, inplace_predicts));
+
+
+    // Multi-thread prediction
+
+    // Reformat the test matrix as 2D array
+    float[][] testX2 = new float[test_rows][features];
+
+    int k=0;
+    for (int i=0; i<test_rows; i++) {
+      for(int j=0; j<features; j++, k++) {
+        testX2[i][j] = testX[k];
+      }
+    }
+
+    // Create thread pool
+    int n_tasks = 20;
+    List<Future<Boolean>> result = new ArrayList(n_tasks);
+    ExecutorService executorService = Executors.newFixedThreadPool(5);  // Create pool of 5 threads
+
+    // Submit all the tasks
+    for (int i=0; i<n_tasks; i++) {
+      result.add(executorService.submit(new InplacePredictionTask(i, booster, testX2, test_rows, features, predicts)));
+    }
+
+    // Tell the executor service we are done
+    executorService.shutdown();
+
+    try {
+      executorService.awaitTermination(10, TimeUnit.SECONDS);
+
+      // Get the result from each Future returned and confirm success
+      for (int i=0; i<n_tasks; i++) {
+        TestCase.assertTrue(result.get(i).get());
+      }
+    } catch (InterruptedException | ExecutionException e) {
+        throw new RuntimeException(e);
+    }
+
+//    System.out.println("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-");
+  }
 
   @Test
   public void saveLoadModelWithPath() throws XGBoostError, IOException {
diff --git a/plugin/CMakeLists.txt b/plugin/CMakeLists.txt
index 485f1cc3c33b..7026238e30cf 100644
--- a/plugin/CMakeLists.txt
+++ b/plugin/CMakeLists.txt
@@ -15,7 +15,7 @@ if (PLUGIN_UPDATER_ONEAPI)
   target_link_libraries(oneapi_plugin PUBLIC -fsycl)
   set_target_properties(oneapi_plugin PROPERTIES
     COMPILE_FLAGS -fsycl
-    CXX_STANDARD 14
+    CXX_STANDARD 17
     CXX_STANDARD_REQUIRED ON
     POSITION_INDEPENDENT_CODE ON)
   if (USE_OPENMP)
diff --git a/python-package/xgboost/VERSION b/python-package/xgboost/VERSION
index de023c91b16b..6a126f402d53 100644
--- a/python-package/xgboost/VERSION
+++ b/python-package/xgboost/VERSION
@@ -1 +1 @@
-1.7.0-dev
+1.7.5
diff --git a/python-package/xgboost/__init__.py b/python-package/xgboost/__init__.py
index 220093b47c4c..f17ac23ba61c 100644
--- a/python-package/xgboost/__init__.py
+++ b/python-package/xgboost/__init__.py
@@ -4,7 +4,7 @@
 """
 
 from . import tracker  # noqa
-from . import collective, dask
+from . import collective, dask, rabit
 from .core import (
     Booster,
     DataIter,
diff --git a/python-package/xgboost/compat.py b/python-package/xgboost/compat.py
index 275b6621064d..3be023abf5af 100644
--- a/python-package/xgboost/compat.py
+++ b/python-package/xgboost/compat.py
@@ -36,13 +36,13 @@ def lazy_isinstance(instance: Any, module: str, name: str) -> bool:
 
     PANDAS_INSTALLED = True
 except ImportError:
-
     MultiIndex = object
     DataFrame = object
     Series = object
     pandas_concat = None
     PANDAS_INSTALLED = False
 
+
 # sklearn
 try:
     from sklearn.base import BaseEstimator as XGBModelBase
@@ -72,6 +72,22 @@ def lazy_isinstance(instance: Any, module: str, name: str) -> bool:
     XGBStratifiedKFold = None
 
 
+_logger = logging.getLogger(__name__)
+
+
+def is_cudf_available() -> bool:
+    """Check cuDF package available or not"""
+    if importlib.util.find_spec("cudf") is None:
+        return False
+    try:
+        import cudf
+
+        return True
+    except ImportError:
+        _logger.exception("Importing cuDF failed, use DMatrix instead of QDM")
+        return False
+
+
 class XGBoostLabelEncoder(LabelEncoder):
     """Label encoder with JSON serialization methods."""
 
@@ -144,6 +160,7 @@ def concat(value: Sequence[_T]) -> _T:  # pylint: disable=too-many-return-statem
 # `importlib.utils`, except it's unclear from its document on how to use it.  This one
 # seems to be easy to understand and works out of box.
 
+
 # Copyright 2015 The TensorFlow Authors. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
diff --git a/python-package/xgboost/core.py b/python-package/xgboost/core.py
index cd028ba0bedf..8a877ec5a824 100644
--- a/python-package/xgboost/core.py
+++ b/python-package/xgboost/core.py
@@ -237,6 +237,7 @@ def parse(ver: str) -> Tuple[int, int, int]:
         """Avoid dependency on packaging (PEP 440)."""
         # 2.0.0-dev or 2.0.0
         major, minor, patch = ver.split("-")[0].split(".")
+        patch = patch.split("rc")[0]  # 2.0.0rc1
         return int(major), int(minor), int(patch)
 
     libver = _lib_version(lib)
@@ -2171,6 +2172,7 @@ def assign_type(t: int) -> None:
         )
         return _prediction_output(shape, dims, preds, False)
 
+    # pylint: disable=too-many-statements
     def inplace_predict(
         self,
         data: DataType,
@@ -2191,10 +2193,10 @@ def inplace_predict(
 
         .. code-block:: python
 
-            booster.set_param({'predictor': 'gpu_predictor'})
+            booster.set_param({"predictor": "gpu_predictor"})
             booster.inplace_predict(cupy_array)
 
-            booster.set_param({'predictor': 'cpu_predictor})
+            booster.set_param({"predictor": "cpu_predictor"})
             booster.inplace_predict(numpy_array)
 
         .. versionadded:: 1.1.0
@@ -2300,14 +2302,16 @@ def inplace_predict(
             )
             return _prediction_output(shape, dims, preds, False)
         if isinstance(data, scipy.sparse.csr_matrix):
-            csr = data
+            from .data import _transform_scipy_csr
+
+            data = _transform_scipy_csr(data)
             _check_call(
                 _LIB.XGBoosterPredictFromCSR(
                     self.handle,
-                    _array_interface(csr.indptr),
-                    _array_interface(csr.indices),
-                    _array_interface(csr.data),
-                    ctypes.c_size_t(csr.shape[1]),
+                    _array_interface(data.indptr),
+                    _array_interface(data.indices),
+                    _array_interface(data.data),
+                    c_bst_ulong(data.shape[1]),
                     from_pystr_to_cstr(json.dumps(args)),
                     p_handle,
                     ctypes.byref(shape),
diff --git a/python-package/xgboost/dask.py b/python-package/xgboost/dask.py
index 7d21ff9fcb48..69d1832f1506 100644
--- a/python-package/xgboost/dask.py
+++ b/python-package/xgboost/dask.py
@@ -853,7 +853,7 @@ async def _get_rabit_args(
         sched_addr = None
 
     # make sure all workers are online so that we can obtain reliable scheduler_info
-    client.wait_for_workers(n_workers)
+    await client.wait_for_workers(n_workers)  # type: ignore
     env = await client.run_on_scheduler(
         _start_tracker, n_workers, sched_addr, user_addr
     )
diff --git a/python-package/xgboost/data.py b/python-package/xgboost/data.py
index e486fb57a5f5..6afc27e156c9 100644
--- a/python-package/xgboost/data.py
+++ b/python-package/xgboost/data.py
@@ -30,6 +30,7 @@
     c_array,
     c_str,
     from_pystr_to_cstr,
+    make_jcargs,
 )
 
 DispatchedDataBackendReturnType = Tuple[
@@ -80,6 +81,21 @@ def _array_interface(data: np.ndarray) -> bytes:
     return interface_str
 
 
+def _transform_scipy_csr(data: DataType) -> DataType:
+    from scipy.sparse import csr_matrix
+
+    indptr, _ = _ensure_np_dtype(data.indptr, data.indptr.dtype)
+    indices, _ = _ensure_np_dtype(data.indices, data.indices.dtype)
+    values, _ = _ensure_np_dtype(data.data, data.data.dtype)
+    if (
+        indptr is not data.indptr
+        or indices is not data.indices
+        or values is not data.data
+    ):
+        data = csr_matrix((values, indices, indptr), shape=data.shape)
+    return data
+
+
 def _from_scipy_csr(
     data: DataType,
     missing: FloatCompatible,
@@ -93,18 +109,14 @@ def _from_scipy_csr(
             f"length mismatch: {len(data.indices)} vs {len(data.data)}"
         )
     handle = ctypes.c_void_p()
-    args = {
-        "missing": float(missing),
-        "nthread": int(nthread),
-    }
-    config = bytes(json.dumps(args), "utf-8")
+    data = _transform_scipy_csr(data)
     _check_call(
         _LIB.XGDMatrixCreateFromCSR(
             _array_interface(data.indptr),
             _array_interface(data.indices),
             _array_interface(data.data),
-            ctypes.c_size_t(data.shape[1]),
-            config,
+            c_bst_ulong(data.shape[1]),
+            make_jcargs(missing=float(missing), nthread=int(nthread)),
             ctypes.byref(handle),
         )
     )
@@ -153,12 +165,13 @@ def _is_numpy_array(data: DataType) -> bool:
 
 
 def _ensure_np_dtype(
-    data: DataType,
-    dtype: Optional[NumpyDType]
+    data: DataType, dtype: Optional[NumpyDType]
 ) -> Tuple[np.ndarray, Optional[NumpyDType]]:
     if data.dtype.hasobject or data.dtype in [np.float16, np.bool_]:
-        data = data.astype(np.float32, copy=False)
         dtype = np.float32
+        data = data.astype(dtype, copy=False)
+    if not data.flags.aligned:
+        data = np.require(data, requirements="A")
     return data, dtype
 
 
@@ -1197,11 +1210,13 @@ def _proxy_transform(
         data, _ = _ensure_np_dtype(data, data.dtype)
         return data, None, feature_names, feature_types
     if _is_scipy_csr(data):
+        data = _transform_scipy_csr(data)
         return data, None, feature_names, feature_types
     if _is_pandas_df(data):
         arr, feature_names, feature_types = _transform_pandas_df(
             data, enable_categorical, feature_names, feature_types
         )
+        arr, _ = _ensure_np_dtype(arr, arr.dtype)
         return arr, None, feature_names, feature_types
     raise TypeError("Value type is not supported for data iterator:" + str(type(data)))
 
diff --git a/python-package/xgboost/rabit.py b/python-package/xgboost/rabit.py
new file mode 100644
index 000000000000..258ec4b6da4e
--- /dev/null
+++ b/python-package/xgboost/rabit.py
@@ -0,0 +1,168 @@
+"""Compatibility shim for xgboost.rabit; to be removed in 2.0"""
+import logging
+import warnings
+from enum import IntEnum, unique
+from typing import Any, TypeVar, Callable, Optional, List
+
+import numpy as np
+
+from . import collective
+
+LOGGER = logging.getLogger("[xgboost.rabit]")
+
+
+def _deprecation_warning() -> str:
+    return (
+        "The xgboost.rabit submodule is marked as deprecated in 1.7 and will be removed "
+        "in 2.0. Please use xgboost.collective instead."
+    )
+
+
+def init(args: Optional[List[bytes]] = None) -> None:
+    """Initialize the rabit library with arguments"""
+    warnings.warn(_deprecation_warning(), FutureWarning)
+    parsed = {}
+    if args:
+        for arg in args:
+            kv = arg.decode().split('=')
+            if len(kv) == 2:
+                parsed[kv[0]] = kv[1]
+    collective.init(**parsed)
+
+
+def finalize() -> None:
+    """Finalize the process, notify tracker everything is done."""
+    collective.finalize()
+
+
+def get_rank() -> int:
+    """Get rank of current process.
+    Returns
+    -------
+    rank : int
+        Rank of current process.
+    """
+    return collective.get_rank()
+
+
+def get_world_size() -> int:
+    """Get total number workers.
+    Returns
+    -------
+    n : int
+        Total number of process.
+    """
+    return collective.get_world_size()
+
+
+def is_distributed() -> int:
+    """If rabit is distributed."""
+    return collective.is_distributed()
+
+
+def tracker_print(msg: Any) -> None:
+    """Print message to the tracker.
+    This function can be used to communicate the information of
+    the progress to the tracker
+    Parameters
+    ----------
+    msg : str
+        The message to be printed to tracker.
+    """
+    collective.communicator_print(msg)
+
+
+def get_processor_name() -> bytes:
+    """Get the processor name.
+    Returns
+    -------
+    name : str
+        the name of processor(host)
+    """
+    return collective.get_processor_name().encode()
+
+
+T = TypeVar("T")  # pylint:disable=invalid-name
+
+
+def broadcast(data: T, root: int) -> T:
+    """Broadcast object from one node to all other nodes.
+    Parameters
+    ----------
+    data : any type that can be pickled
+        Input data, if current rank does not equal root, this can be None
+    root : int
+        Rank of the node to broadcast data from.
+    Returns
+    -------
+    object : int
+        the result of broadcast.
+    """
+    return collective.broadcast(data, root)
+
+
+@unique
+class Op(IntEnum):
+    """Supported operations for rabit."""
+    MAX = 0
+    MIN = 1
+    SUM = 2
+    OR = 3
+
+
+def allreduce(  # pylint:disable=invalid-name
+        data: np.ndarray, op: Op, prepare_fun: Optional[Callable[[np.ndarray], None]] = None
+) -> np.ndarray:
+    """Perform allreduce, return the result.
+    Parameters
+    ----------
+    data :
+        Input data.
+    op :
+        Reduction operators, can be MIN, MAX, SUM, BITOR
+    prepare_fun :
+        Lazy preprocessing function, if it is not None, prepare_fun(data)
+        will be called by the function before performing allreduce, to initialize the data
+        If the result of Allreduce can be recovered directly,
+        then prepare_fun will NOT be called
+    Returns
+    -------
+    result :
+        The result of allreduce, have same shape as data
+    Notes
+    -----
+    This function is not thread-safe.
+    """
+    if prepare_fun is None:
+        return collective.allreduce(data, collective.Op(op))
+    raise Exception("preprocessing function is no longer supported")
+
+
+def version_number() -> int:
+    """Returns version number of current stored model.
+    This means how many calls to CheckPoint we made so far.
+    Returns
+    -------
+    version : int
+        Version number of currently stored model
+    """
+    return 0
+
+
+class RabitContext:
+    """A context controlling rabit initialization and finalization."""
+
+    def __init__(self, args: List[bytes] = None) -> None:
+        if args is None:
+            args = []
+        self.args = args
+
+    def __enter__(self) -> None:
+        init(self.args)
+        assert is_distributed()
+        LOGGER.warning(_deprecation_warning())
+        LOGGER.debug("-------------- rabit say hello ------------------")
+
+    def __exit__(self, *args: List) -> None:
+        finalize()
+        LOGGER.debug("--------------- rabit say bye ------------------")
diff --git a/python-package/xgboost/sklearn.py b/python-package/xgboost/sklearn.py
index 5a873ab88be3..49687e2fbf6c 100644
--- a/python-package/xgboost/sklearn.py
+++ b/python-package/xgboost/sklearn.py
@@ -674,7 +674,7 @@ def set_params(self, **params: Any) -> "XGBModel":
                     self.kwargs = {}
                 self.kwargs[key] = value
 
-        if hasattr(self, "_Booster"):
+        if self.__sklearn_is_fitted__():
             parameters = self.get_xgb_params()
             self.get_booster().set_param(parameters)
 
@@ -701,39 +701,12 @@ def get_params(self, deep: bool = True) -> Dict[str, Any]:
                 np.iinfo(np.int32).max
             )
 
-        def parse_parameter(value: Any) -> Optional[Union[int, float, str]]:
-            for t in (int, float, str):
-                try:
-                    ret = t(value)
-                    return ret
-                except ValueError:
-                    continue
-            return None
-
-        # Get internal parameter values
-        try:
-            config = json.loads(self.get_booster().save_config())
-            stack = [config]
-            internal = {}
-            while stack:
-                obj = stack.pop()
-                for k, v in obj.items():
-                    if k.endswith("_param"):
-                        for p_k, p_v in v.items():
-                            internal[p_k] = p_v
-                    elif isinstance(v, dict):
-                        stack.append(v)
-
-            for k, v in internal.items():
-                if k in params and params[k] is None:
-                    params[k] = parse_parameter(v)
-        except ValueError:
-            pass
         return params
 
     def get_xgb_params(self) -> Dict[str, Any]:
         """Get xgboost specific parameters."""
-        params = self.get_params()
+        params: Dict[str, Any] = self.get_params()
+
         # Parameters that should not go into native learner.
         wrapper_specific = {
             "importance_type",
@@ -750,6 +723,7 @@ def get_xgb_params(self) -> Dict[str, Any]:
         for k, v in params.items():
             if k not in wrapper_specific and not callable(v):
                 filtered[k] = v
+
         return filtered
 
     def get_num_boosting_rounds(self) -> int:
@@ -1070,7 +1044,7 @@ def _can_use_inplace_predict(self) -> bool:
         # error with incompatible data type.
         # Inplace predict doesn't handle as many data types as DMatrix, but it's
         # sufficient for dask interface where input is simpiler.
-        predictor = self.get_params().get("predictor", None)
+        predictor = self.get_xgb_params().get("predictor", None)
         if predictor in ("auto", None) and self.booster != "gblinear":
             return True
         return False
@@ -1336,7 +1310,7 @@ def coef_(self) -> np.ndarray:
         -------
         coef_ : array of shape ``[n_features]`` or ``[n_classes, n_features]``
         """
-        if self.get_params()["booster"] != "gblinear":
+        if self.get_xgb_params()["booster"] != "gblinear":
             raise AttributeError(
                 f"Coefficients are not defined for Booster type {self.booster}"
             )
@@ -1366,7 +1340,7 @@ def intercept_(self) -> np.ndarray:
         -------
         intercept_ : array of shape ``(1,)`` or ``[n_classes]``
         """
-        if self.get_params()["booster"] != "gblinear":
+        if self.get_xgb_params()["booster"] != "gblinear":
             raise AttributeError(
                 f"Intercept (bias) is not defined for Booster type {self.booster}"
             )
diff --git a/python-package/xgboost/spark/__init__.py b/python-package/xgboost/spark/__init__.py
index c0b347eefb30..2720532c0411 100644
--- a/python-package/xgboost/spark/__init__.py
+++ b/python-package/xgboost/spark/__init__.py
@@ -1,6 +1,5 @@
 # type: ignore
-"""PySpark XGBoost integration interface
-"""
+"""PySpark XGBoost integration interface"""
 
 try:
     import pyspark
@@ -11,6 +10,7 @@
     SparkXGBClassifier,
     SparkXGBClassifierModel,
     SparkXGBRanker,
+    SparkXGBRankerModel,
     SparkXGBRegressor,
     SparkXGBRegressorModel,
 )
@@ -21,4 +21,5 @@
     "SparkXGBRegressor",
     "SparkXGBRegressorModel",
     "SparkXGBRanker",
+    "SparkXGBRankerModel",
 ]
diff --git a/python-package/xgboost/spark/core.py b/python-package/xgboost/spark/core.py
index 1e544c34f228..4f770e139a27 100644
--- a/python-package/xgboost/spark/core.py
+++ b/python-package/xgboost/spark/core.py
@@ -1,7 +1,7 @@
 # type: ignore
 """Xgboost pyspark integration submodule for core code."""
 # pylint: disable=fixme, too-many-ancestors, protected-access, no-member, invalid-name
-# pylint: disable=too-few-public-methods, too-many-lines
+# pylint: disable=too-few-public-methods, too-many-lines, too-many-branches
 import json
 from typing import Iterator, Optional, Tuple
 
@@ -32,6 +32,7 @@
     ShortType,
 )
 from scipy.special import expit, softmax  # pylint: disable=no-name-in-module
+from xgboost.compat import is_cudf_available
 from xgboost.core import Booster
 from xgboost.training import train as worker_train
 
@@ -139,6 +140,13 @@
 }
 
 
+# TODO: supply hint message for all other unsupported params.
+_unsupported_params_hint_message = {
+    "enable_categorical": "`xgboost.spark` estimators do not have 'enable_categorical' param, "
+    "but you can set `feature_types` param and mark categorical features with 'c' string."
+}
+
+
 class _SparkXGBParams(
     HasFeaturesCol,
     HasLabelCol,
@@ -522,7 +530,10 @@ def setParams(self, **kwargs):  # pylint: disable=invalid-name
                     or k in _unsupported_predict_params
                     or k in _unsupported_train_params
                 ):
-                    raise ValueError(f"Unsupported param '{k}'.")
+                    err_msg = _unsupported_params_hint_message.get(
+                        k, f"Unsupported param '{k}'."
+                    )
+                    raise ValueError(err_msg)
                 _extra_params[k] = v
         _existing_extra_params = self.getOrDefault(self.arbitrary_params_dict)
         self._set(arbitrary_params_dict={**_existing_extra_params, **_extra_params})
@@ -728,6 +739,10 @@ def _fit(self, dataset):
             else:
                 dataset = dataset.repartition(num_workers)
 
+        if self.isDefined(self.qid_col) and self.getOrDefault(self.qid_col):
+            # XGBoost requires qid to be sorted for each partition
+            dataset = dataset.sortWithinPartitions(alias.qid, ascending=True)
+
         train_params = self._get_distributed_train_params(dataset)
         booster_params, train_call_kwargs_params = self._get_xgb_train_call_args(
             train_params
@@ -744,6 +759,8 @@ def _fit(self, dataset):
             "feature_weights": self.getOrDefault(self.feature_weights),
             "missing": float(self.getOrDefault(self.missing)),
         }
+        if dmatrix_kwargs["feature_types"] is not None:
+            dmatrix_kwargs["enable_categorical"] = True
         booster_params["nthread"] = cpu_per_task
         use_gpu = self.getOrDefault(self.use_gpu)
 
@@ -755,7 +772,8 @@ def _fit(self, dataset):
             k: v for k, v in train_call_kwargs_params.items() if v is not None
         }
         dmatrix_kwargs = {k: v for k, v in dmatrix_kwargs.items() if v is not None}
-        use_qdm = booster_params.get("tree_method", None) in ("hist", "gpu_hist")
+
+        use_hist = booster_params.get("tree_method", None) in ("hist", "gpu_hist")
 
         def _train_booster(pandas_df_iter):
             """Takes in an RDD partition and outputs a booster for that partition after
@@ -769,6 +787,15 @@ def _train_booster(pandas_df_iter):
 
             gpu_id = None
 
+            # If cuDF is not installed, then using DMatrix instead of QDM,
+            # because without cuDF, DMatrix performs better than QDM.
+            # Note: Checking `is_cudf_available` in spark worker side because
+            # spark worker might has different python environment with driver side.
+            if use_gpu:
+                use_qdm = use_hist and is_cudf_available()
+            else:
+                use_qdm = use_hist
+
             if use_qdm and (booster_params.get("max_bin", None) is not None):
                 dmatrix_kwargs["max_bin"] = booster_params["max_bin"]
 
diff --git a/rabit/CMakeLists.txt b/rabit/CMakeLists.txt
index ad39fb249791..ab8171b2b0b9 100644
--- a/rabit/CMakeLists.txt
+++ b/rabit/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.3)
+cmake_minimum_required(VERSION 3.18)
 
 find_package(Threads REQUIRED)
 
diff --git a/src/c_api/c_api.cc b/src/c_api/c_api.cc
index 87a30283f925..d5dbb98bd2d6 100644
--- a/src/c_api/c_api.cc
+++ b/src/c_api/c_api.cc
@@ -322,7 +322,7 @@ XGB_DLL int XGQuantileDMatrixCreateFromCallback(DataIterHandle iter, DMatrixHand
 XGB_DLL int XGProxyDMatrixCreate(DMatrixHandle* out) {
   API_BEGIN();
   xgboost_CHECK_C_ARG_PTR(out);
-  *out = new std::shared_ptr<xgboost::DMatrix>(new xgboost::data::DMatrixProxy);;
+  *out = new std::shared_ptr<xgboost::DMatrix>(new xgboost::data::DMatrixProxy);
   API_END();
 }
 
@@ -968,6 +968,27 @@ XGB_DLL int XGBoosterPredictFromDMatrix(BoosterHandle handle,
   API_END();
 }
 
+void InplacePredictImplCore(std::shared_ptr<DMatrix> p_m,
+                            Learner *learner,
+                            xgboost::PredictionType type,
+                            float missing,
+                            size_t n_rows, size_t n_cols,
+                            size_t iteration_begin, size_t iteration_end,
+                            bool strict_shape,
+                            xgboost::bst_ulong const **out_shape,
+                            xgboost::bst_ulong *out_dim, const float **out_result) {
+  HostDeviceVector<float>* p_predt { nullptr };
+  learner->InplacePredict(p_m, type, missing, &p_predt, iteration_begin, iteration_end);
+  CHECK(p_predt);
+  auto &shape = learner->GetThreadLocal().prediction_shape;
+  auto chunksize = n_rows == 0 ? 0 : p_predt->Size() / n_rows;
+  CalcPredictShape(strict_shape, type, n_rows, n_cols, chunksize, learner->Groups(),
+                   learner->BoostedRounds(), &shape, out_dim);
+  *out_result = dmlc::BeginPtr(p_predt->HostVector());
+  *out_shape = dmlc::BeginPtr(shape);
+//  printf("InplacePredictImplCore shape = %u, dim = %u\n", **out_shape, *out_dim);
+}
+
 void InplacePredictImpl(std::shared_ptr<DMatrix> p_m, char const *c_json_config, Learner *learner,
                         xgboost::bst_ulong const **out_shape, xgboost::bst_ulong *out_dim,
                         const float **out_result) {
@@ -975,29 +996,45 @@ void InplacePredictImpl(std::shared_ptr<DMatrix> p_m, char const *c_json_config,
   auto config = Json::Load(StringView{c_json_config});
   CHECK_EQ(get<Integer const>(config["cache_id"]), 0) << "Cache ID is not supported yet";
 
-  HostDeviceVector<float> *p_predt{nullptr};
   auto type = PredictionType(RequiredArg<Integer>(config, "type", __func__));
   float missing = GetMissing(config);
-  learner->InplacePredict(p_m, type, missing, &p_predt,
-                          RequiredArg<Integer>(config, "iteration_begin", __func__),
-                          RequiredArg<Integer>(config, "iteration_end", __func__));
-  CHECK(p_predt);
-  auto &shape = learner->GetThreadLocal().prediction_shape;
   auto const &info = p_m->Info();
   auto n_samples = info.num_row_;
   auto n_features = info.num_col_;
-  auto chunksize = n_samples == 0 ? 0 : p_predt->Size() / n_samples;
+  int iteration_begin = get<Integer const>(config["iteration_begin"]);
+  int iteration_end   = get<Integer const>(config["iteration_end"]);
   bool strict_shape = RequiredArg<Boolean>(config, "strict_shape", __func__);
 
   xgboost_CHECK_C_ARG_PTR(out_dim);
-  CalcPredictShape(strict_shape, type, n_samples, n_features, chunksize, learner->Groups(),
-                   learner->BoostedRounds(), &shape, out_dim);
 
   xgboost_CHECK_C_ARG_PTR(out_result);
   xgboost_CHECK_C_ARG_PTR(out_shape);
 
-  *out_result = dmlc::BeginPtr(p_predt->HostVector());
-  *out_shape = dmlc::BeginPtr(shape);
+  InplacePredictImplCore(p_m, learner, type, missing, n_samples, n_features,
+                         iteration_begin, iteration_end, strict_shape, out_shape, out_dim, out_result);
+}
+
+XGB_DLL int XGBoosterInplacePredict(BoosterHandle handle,
+                                    const float *data,
+                                    size_t num_rows,
+                                    size_t num_features,
+                                    DMatrixHandle dMatrixHandle,
+                                    float missing,
+                                    int option_mask,
+                                    int ntree_limit,
+                                    const xgboost::bst_ulong **len,
+                                    const bst_float **out_result) {
+  API_BEGIN();
+  CHECK_HANDLE();
+  xgboost::bst_ulong out_dim;
+
+  auto *learner = static_cast<xgboost::Learner *>(handle);
+  auto iteration_end = GetIterationFromTreeLimit(ntree_limit, learner);
+  auto proxy = std::make_shared<data::DMatrixProxy>();
+  proxy->SetDenseData(data, num_rows, num_features);
+  InplacePredictImplCore(proxy, learner, (xgboost::PredictionType)0, missing, num_rows, num_features,
+                         0, iteration_end, true, len, &out_dim, out_result);
+  API_END();
 }
 
 XGB_DLL int XGBoosterPredictFromDense(BoosterHandle handle, char const *array_interface,
diff --git a/src/common/categorical.h b/src/common/categorical.h
index ead5f570c44f..452aaa8c1cdc 100644
--- a/src/common/categorical.h
+++ b/src/common/categorical.h
@@ -48,20 +48,21 @@ inline XGBOOST_DEVICE bool InvalidCat(float cat) {
   return cat < 0 || cat >= kMaxCat;
 }
 
-/* \brief Whether should it traverse to left branch of a tree.
+/**
+ * \brief Whether should it traverse to left branch of a tree.
  *
- *  For one hot split, go to left if it's NOT the matching category.
+ *   Go to left if it's NOT the matching category, which matches one-hot encoding.
  */
-template <bool validate = true>
-inline XGBOOST_DEVICE bool Decision(common::Span<uint32_t const> cats, float cat, bool dft_left) {
+inline XGBOOST_DEVICE bool Decision(common::Span<uint32_t const> cats, float cat) {
   KCatBitField const s_cats(cats);
-  // FIXME: Size() is not accurate since it represents the size of bit set instead of
-  // actual number of categories.
-  if (XGBOOST_EXPECT(validate && (InvalidCat(cat) || cat >= s_cats.Size()), false)) {
-    return dft_left;
+  if (XGBOOST_EXPECT(InvalidCat(cat), false)) {
+    return true;
   }
 
   auto pos = KCatBitField::ToBitPos(cat);
+  // If the input category is larger than the size of the bit field, it implies that the
+  // category is not chosen. Otherwise the bit field would have the category instead of
+  // being smaller than the category value.
   if (pos.int_pos >= cats.size()) {
     return true;
   }
diff --git a/src/common/column_matrix.cc b/src/common/column_matrix.cc
index 91977b96dcdf..d8acfa7a5570 100644
--- a/src/common/column_matrix.cc
+++ b/src/common/column_matrix.cc
@@ -46,7 +46,7 @@ void ColumnMatrix::InitStorage(GHistIndexMatrix const& gmat, double sparse_thres
     feature_offsets_[fid] = accum_index;
   }
 
-  SetTypeSize(gmat.max_num_bins);
+  SetTypeSize(gmat.MaxNumBinPerFeat());
   auto storage_size =
       feature_offsets_.back() * static_cast<std::underlying_type_t<BinTypeSize>>(bins_type_size_);
   index_.resize(storage_size, 0);
diff --git a/src/common/cuda_pinned_allocator.h b/src/common/cuda_pinned_allocator.h
new file mode 100644
index 000000000000..d11851d99d37
--- /dev/null
+++ b/src/common/cuda_pinned_allocator.h
@@ -0,0 +1,91 @@
+/*!
+ * Copyright 2022 by XGBoost Contributors
+ * \file common.h
+ * \brief cuda pinned allocator for usage with thrust containers
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <limits>
+
+#include "common.h"
+
+namespace xgboost {
+namespace common {
+namespace cuda {
+
+// \p pinned_allocator is a CUDA-specific host memory allocator
+//  that employs \c cudaMallocHost for allocation.
+//
+// This implementation is ported from the experimental/pinned_allocator
+// that Thrust used to provide.
+//
+//  \see https://en.cppreference.com/w/cpp/memory/allocator
+template <typename T>
+class pinned_allocator;
+
+template <>
+class pinned_allocator<void> {
+ public:
+  using value_type      = void;            // NOLINT: The type of the elements in the allocator
+  using pointer         = void*;           // NOLINT: The type returned by address() / allocate()
+  using const_pointer   = const void*;     // NOLINT: The type returned by address()
+  using size_type       = std::size_t;     // NOLINT: The type used for the size of the allocation
+  using difference_type = std::ptrdiff_t;  // NOLINT: The type of the distance between two pointers
+
+  template <typename U>
+  struct rebind {                       // NOLINT
+    using other = pinned_allocator<U>;  // NOLINT: The rebound type
+  };
+};
+
+
+template <typename T>
+class pinned_allocator {
+ public:
+  using value_type      = T;               // NOLINT: The type of the elements in the allocator
+  using pointer         = T*;              // NOLINT: The type returned by address() / allocate()
+  using const_pointer   = const T*;        // NOLINT: The type returned by address()
+  using reference       = T&;              // NOLINT: The parameter type for address()
+  using const_reference = const T&;        // NOLINT: The parameter type for address()
+  using size_type       = std::size_t;     // NOLINT: The type used for the size of the allocation
+  using difference_type = std::ptrdiff_t;  // NOLINT: The type of the distance between two pointers
+
+  template <typename U>
+  struct rebind {                       // NOLINT
+    using other = pinned_allocator<U>;  // NOLINT: The rebound type
+  };
+
+  XGBOOST_DEVICE inline pinned_allocator() {}; // NOLINT: host/device markup ignored on defaulted functions
+  XGBOOST_DEVICE inline ~pinned_allocator() {} // NOLINT: host/device markup ignored on defaulted functions
+  XGBOOST_DEVICE inline pinned_allocator(pinned_allocator const&) {} // NOLINT: host/device markup ignored on defaulted functions
+
+
+  template <typename U>
+  XGBOOST_DEVICE inline pinned_allocator(pinned_allocator<U> const&) {} // NOLINT
+
+  XGBOOST_DEVICE inline pointer address(reference r) { return &r; } // NOLINT
+  XGBOOST_DEVICE inline const_pointer address(const_reference r) { return &r; } // NOLINT
+
+  inline pointer allocate(size_type cnt, const_pointer = nullptr) { // NOLINT
+    if (cnt > this->max_size()) { throw std::bad_alloc(); }  // end if
+
+    pointer result(nullptr);
+    dh::safe_cuda(cudaMallocHost(reinterpret_cast<void**>(&result), cnt * sizeof(value_type)));
+    return result;
+  }
+
+  inline void deallocate(pointer p, size_type) { dh::safe_cuda(cudaFreeHost(p)); } // NOLINT
+
+  inline size_type max_size() const { return (std::numeric_limits<size_type>::max)() / sizeof(T); } // NOLINT
+
+  XGBOOST_DEVICE inline bool operator==(pinned_allocator const& x) const { return true; }
+
+  XGBOOST_DEVICE inline bool operator!=(pinned_allocator const& x) const {
+    return !operator==(x);
+  }
+};
+}  // namespace cuda
+}  // namespace common
+}  // namespace xgboost
diff --git a/src/common/linalg_op.h b/src/common/linalg_op.h
index efb9cf300238..26cb405f526f 100644
--- a/src/common/linalg_op.h
+++ b/src/common/linalg_op.h
@@ -62,7 +62,7 @@ void ElementWiseKernel(GenericParameter const* ctx, linalg::TensorView<T, D> t,
 #endif  // !defined(XGBOOST_USE_CUDA)
 
 template <typename T, std::int32_t kDim>
-auto cbegin(TensorView<T, kDim> v) {  // NOLINT
+auto cbegin(TensorView<T, kDim> const& v) {  // NOLINT
   auto it = common::MakeIndexTransformIter([&](size_t i) -> std::remove_cv_t<T> const& {
     return linalg::detail::Apply(v, linalg::UnravelIndex(i, v.Shape()));
   });
@@ -70,19 +70,19 @@ auto cbegin(TensorView<T, kDim> v) {  // NOLINT
 }
 
 template <typename T, std::int32_t kDim>
-auto cend(TensorView<T, kDim> v) {  // NOLINT
+auto cend(TensorView<T, kDim> const& v) {  // NOLINT
   return cbegin(v) + v.Size();
 }
 
 template <typename T, std::int32_t kDim>
-auto begin(TensorView<T, kDim> v) {  // NOLINT
+auto begin(TensorView<T, kDim>& v) {  // NOLINT
   auto it = common::MakeIndexTransformIter(
       [&](size_t i) -> T& { return linalg::detail::Apply(v, linalg::UnravelIndex(i, v.Shape())); });
   return it;
 }
 
 template <typename T, std::int32_t kDim>
-auto end(TensorView<T, kDim> v) {  // NOLINT
+auto end(TensorView<T, kDim>& v) {  // NOLINT
   return begin(v) + v.Size();
 }
 }  // namespace linalg
diff --git a/src/common/partition_builder.h b/src/common/partition_builder.h
index 34864ee90679..568e611b732d 100644
--- a/src/common/partition_builder.h
+++ b/src/common/partition_builder.h
@@ -144,7 +144,7 @@ class PartitionBuilder {
         auto gidx = gidx_calc(ridx);
         bool go_left = default_left;
         if (gidx > -1) {
-          go_left = Decision(node_cats, cut_values[gidx], default_left);
+          go_left = Decision(node_cats, cut_values[gidx]);
         }
         return go_left;
       } else {
@@ -157,7 +157,7 @@ class PartitionBuilder {
       bool go_left = default_left;
       if (gidx > -1) {
         if (is_cat) {
-          go_left = Decision(node_cats, cut_values[gidx], default_left);
+          go_left = Decision(node_cats, cut_values[gidx]);
         } else {
           go_left = cut_values[gidx] <= nodes[node_in_set].split.split_value;
         }
diff --git a/src/common/threading_utils.cc b/src/common/threading_utils.cc
index bcff45efbd1e..f44e9aa99aa5 100644
--- a/src/common/threading_utils.cc
+++ b/src/common/threading_utils.cc
@@ -5,47 +5,61 @@
 
 #include <fstream>
 #include <string>
+#include <mutex>
 
 #include "xgboost/logging.h"
 
 namespace xgboost {
 namespace common {
+
 /**
- * \brief Get thread limit from CFS
- *
- * Modified from
- * github.com/psiha/sweater/blob/master/include/boost/sweater/hardware_concurrency.hpp
+ * \brief Read an integer value from a system file.
  *
- * MIT License: Copyright (c) 2016 Domagoj Šarić
+ * \param file_path Path to the system file.
+ * \return Parsed integer value, or -1 if reading fails.
  */
-int32_t GetCfsCPUCount() noexcept {
-#if defined(__linux__)
-  // https://bugs.openjdk.java.net/browse/JDK-8146115
-  // http://hg.openjdk.java.net/jdk/hs/rev/7f22774a5f42
-  // RAM limit /sys/fs/cgroup/memory.limit_in_bytes
-  // swap limt /sys/fs/cgroup/memory.memsw.limit_in_bytes
-
-  auto read_int = [](char const* const file_path) noexcept {
+int ReadIntFromFile(const char* file_path) noexcept {
     std::ifstream fin(file_path);
     if (!fin) {
-      return -1;
+        return -1;  // Return -1 on failure
     }
+
     std::string value;
     fin >> value;
+
     try {
-      return std::stoi(value);
-    } catch (std::exception const&) {
-      return -1;
+        return std::stoi(value);
+    } catch (const std::exception&) {
+        return -1;  // Return -1 if parsing fails
     }
-  };
-  // complete fair scheduler from Linux
-  auto const cfs_quota(read_int("/sys/fs/cgroup/cpu/cpu.cfs_quota_us"));
-  auto const cfs_period(read_int("/sys/fs/cgroup/cpu/cpu.cfs_period_us"));
-  if ((cfs_quota > 0) && (cfs_period > 0)) {
-    return std::max(cfs_quota / cfs_period, 1);
-  }
-#endif  //  defined(__linux__)
-  return -1;
 }
+
+/**
+ * \brief Get thread limit from the CFS scheduler.
+ *
+ * This function caches the result to avoid repeated file system access.
+ *
+ * \return The computed thread limit or -1 if unavailable.
+ */
+int32_t GetCfsCPUCount() noexcept {
+    static int32_t cached_cfs_cpu_count = -2;
+    static std::once_flag cache_flag;
+
+    std::call_once(cache_flag, []() {
+#if defined(__linux__)
+        const int cfs_quota = ReadIntFromFile("/sys/fs/cgroup/cpu/cpu.cfs_quota_us");
+        const int cfs_period = ReadIntFromFile("/sys/fs/cgroup/cpu/cpu.cfs_period_us");
+
+        if (cfs_quota > 0 && cfs_period > 0) {
+            cached_cfs_cpu_count = std::max(cfs_quota / cfs_period, 1);
+            return;
+        }
+#endif  // defined(__linux__)
+        cached_cfs_cpu_count = -1;  // Default to -1 if no valid quota is found
+    });
+
+    return cached_cfs_cpu_count;
+}
+
 }  // namespace common
 }  // namespace xgboost
diff --git a/src/data/array_interface.h b/src/data/array_interface.h
index 0d7b4681accb..a833fe9e8e3d 100644
--- a/src/data/array_interface.h
+++ b/src/data/array_interface.h
@@ -1,5 +1,5 @@
-/*!
- * Copyright 2019-2021 by Contributors
+/**
+ * Copyright 2019-2023 by XGBoost Contributors
  * \file array_interface.h
  * \brief View of __array_interface__
  */
@@ -7,9 +7,11 @@
 #define XGBOOST_DATA_ARRAY_INTERFACE_H_
 
 #include <algorithm>
-#include <cinttypes>
+#include <cstddef>  // std::size_t
+#include <cstdint>
 #include <map>
 #include <string>
+#include <type_traits>  // std::alignment_of,std::remove_pointer_t
 #include <utility>
 #include <vector>
 
@@ -101,7 +103,7 @@ class ArrayInterfaceHandler {
   template <typename PtrType>
   static PtrType GetPtrFromArrayData(Object::Map const &obj) {
     auto data_it = obj.find("data");
-    if (data_it == obj.cend()) {
+    if (data_it == obj.cend() || IsA<Null>(data_it->second)) {
       LOG(FATAL) << "Empty data passed in.";
     }
     auto p_data = reinterpret_cast<PtrType>(
@@ -111,7 +113,7 @@ class ArrayInterfaceHandler {
 
   static void Validate(Object::Map const &array) {
     auto version_it = array.find("version");
-    if (version_it == array.cend()) {
+    if (version_it == array.cend() || IsA<Null>(version_it->second)) {
       LOG(FATAL) << "Missing `version' field for array interface";
     }
     if (get<Integer const>(version_it->second) > 3) {
@@ -119,17 +121,19 @@ class ArrayInterfaceHandler {
     }
 
     auto typestr_it = array.find("typestr");
-    if (typestr_it == array.cend()) {
+    if (typestr_it == array.cend() || IsA<Null>(typestr_it->second)) {
       LOG(FATAL) << "Missing `typestr' field for array interface";
     }
 
     auto typestr = get<String const>(typestr_it->second);
     CHECK(typestr.size() == 3 || typestr.size() == 4) << ArrayInterfaceErrors::TypestrFormat();
 
-    if (array.find("shape") == array.cend()) {
+    auto shape_it = array.find("shape");
+    if (shape_it == array.cend() || IsA<Null>(shape_it->second)) {
       LOG(FATAL) << "Missing `shape' field for array interface";
     }
-    if (array.find("data") == array.cend()) {
+    auto data_it = array.find("data");
+    if (data_it == array.cend() || IsA<Null>(data_it->second)) {
       LOG(FATAL) << "Missing `data' field for array interface";
     }
   }
@@ -139,8 +143,9 @@ class ArrayInterfaceHandler {
   static size_t ExtractMask(Object::Map const &column,
                             common::Span<RBitField8::value_type> *p_out) {
     auto &s_mask = *p_out;
-    if (column.find("mask") != column.cend()) {
-      auto const &j_mask = get<Object const>(column.at("mask"));
+    auto const &mask_it = column.find("mask");
+    if (mask_it != column.cend() && !IsA<Null>(mask_it->second)) {
+      auto const &j_mask = get<Object const>(mask_it->second);
       Validate(j_mask);
 
       auto p_mask = GetPtrFromArrayData<RBitField8::value_type *>(j_mask);
@@ -173,8 +178,9 @@ class ArrayInterfaceHandler {
       // assume 1 byte alignment.
       size_t const span_size = RBitField8::ComputeStorageSize(n_bits);
 
-      if (j_mask.find("strides") != j_mask.cend()) {
-        auto strides = get<Array const>(column.at("strides"));
+      auto strides_it = j_mask.find("strides");
+      if (strides_it != j_mask.cend() && !IsA<Null>(strides_it->second)) {
+        auto strides = get<Array const>(strides_it->second);
         CHECK_EQ(strides.size(), 1) << ArrayInterfaceErrors::Dimension(1);
         CHECK_EQ(get<Integer>(strides.at(0)), type_length) << ArrayInterfaceErrors::Contiguous();
       }
@@ -390,6 +396,11 @@ class ArrayInterface {
 
     data = ArrayInterfaceHandler::ExtractData(array, n);
     static_assert(allow_mask ? D == 1 : D >= 1, "Masked ndarray is not supported.");
+
+    auto alignment = this->ElementAlignment();
+    auto ptr = reinterpret_cast<uintptr_t>(this->data);
+    CHECK_EQ(ptr % alignment, 0) << "Input pointer misalignment.";
+
     if (allow_mask) {
       common::Span<RBitField8::value_type> s_mask;
       size_t n_bits = ArrayInterfaceHandler::ExtractMask(array, &s_mask);
@@ -401,7 +412,9 @@ class ArrayInterface {
                             << "XGBoost doesn't support internal broadcasting.";
       }
     } else {
-      CHECK(array.find("mask") == array.cend()) << "Masked array is not yet supported.";
+      auto mask_it = array.find("mask");
+      CHECK(mask_it == array.cend() || IsA<Null>(mask_it->second))
+          << "Masked array is not yet supported.";
     }
 
     auto stream_it = array.find("stream");
@@ -506,9 +519,15 @@ class ArrayInterface {
     return func(reinterpret_cast<uint64_t const *>(data));
   }
 
-  XGBOOST_DEVICE size_t ElementSize() {
-    return this->DispatchCall(
-        [](auto *p_values) { return sizeof(std::remove_pointer_t<decltype(p_values)>); });
+  XGBOOST_DEVICE std::size_t ElementSize() const {
+    return this->DispatchCall([](auto *typed_data_ptr) {
+      return sizeof(std::remove_pointer_t<decltype(typed_data_ptr)>);
+    });
+  }
+  XGBOOST_DEVICE std::size_t ElementAlignment() const {
+    return this->DispatchCall([](auto *typed_data_ptr) {
+      return std::alignment_of<std::remove_pointer_t<decltype(typed_data_ptr)>>::value;
+    });
   }
 
   template <typename T = float, typename... Index>
diff --git a/src/data/gradient_index.cc b/src/data/gradient_index.cc
index 2e9d38a1918c..a2d140a03edf 100644
--- a/src/data/gradient_index.cc
+++ b/src/data/gradient_index.cc
@@ -20,13 +20,13 @@ GHistIndexMatrix::GHistIndexMatrix() : columns_{std::make_unique<common::ColumnM
 
 GHistIndexMatrix::GHistIndexMatrix(DMatrix *p_fmat, bst_bin_t max_bins_per_feat,
                                    double sparse_thresh, bool sorted_sketch, int32_t n_threads,
-                                   common::Span<float> hess) {
+                                   common::Span<float> hess)
+    : max_numeric_bins_per_feat{max_bins_per_feat} {
   CHECK(p_fmat->SingleColBlock());
   // We use sorted sketching for approx tree method since it's more efficient in
   // computation time (but higher memory usage).
   cut = common::SketchOnDMatrix(p_fmat, max_bins_per_feat, n_threads, sorted_sketch, hess);
 
-  max_num_bins = max_bins_per_feat;
   const uint32_t nbins = cut.Ptrs().back();
   hit_count.resize(nbins, 0);
   hit_count_tloc_.resize(n_threads * nbins, 0);
@@ -63,7 +63,7 @@ GHistIndexMatrix::GHistIndexMatrix(MetaInfo const &info, common::HistogramCuts &
     : row_ptr(info.num_row_ + 1, 0),
       hit_count(cuts.TotalBins(), 0),
       cut{std::forward<common::HistogramCuts>(cuts)},
-      max_num_bins(max_bin_per_feat),
+      max_numeric_bins_per_feat(max_bin_per_feat),
       isDense_{info.num_col_ * info.num_row_ == info.num_nonzero_} {}
 
 #if !defined(XGBOOST_USE_CUDA)
@@ -86,13 +86,13 @@ void GHistIndexMatrix::PushBatch(SparsePage const &batch, common::Span<FeatureTy
 }
 
 GHistIndexMatrix::GHistIndexMatrix(SparsePage const &batch, common::Span<FeatureType const> ft,
-                                   common::HistogramCuts const &cuts, int32_t max_bins_per_feat,
-                                   bool isDense, double sparse_thresh, int32_t n_threads) {
+                                   common::HistogramCuts cuts, int32_t max_bins_per_feat,
+                                   bool isDense, double sparse_thresh, int32_t n_threads)
+    : cut{std::move(cuts)},
+      max_numeric_bins_per_feat{max_bins_per_feat},
+      base_rowid{batch.base_rowid},
+      isDense_{isDense} {
   CHECK_GE(n_threads, 1);
-  base_rowid = batch.base_rowid;
-  isDense_ = isDense;
-  cut = cuts;
-  max_num_bins = max_bins_per_feat;
   CHECK_EQ(row_ptr.size(), 0);
   // The number of threads is pegged to the batch size. If the OMP
   // block is parallelized on anything other than the batch/block size,
@@ -127,12 +127,13 @@ INSTANTIATION_PUSH(data::SparsePageAdapterBatch)
 #undef INSTANTIATION_PUSH
 
 void GHistIndexMatrix::ResizeIndex(const size_t n_index, const bool isDense) {
-  if ((max_num_bins - 1 <= static_cast<int>(std::numeric_limits<uint8_t>::max())) && isDense) {
+  if ((MaxNumBinPerFeat() - 1 <= static_cast<int>(std::numeric_limits<uint8_t>::max())) &&
+      isDense) {
     // compress dense index to uint8
     index.SetBinTypeSize(common::kUint8BinsTypeSize);
     index.Resize((sizeof(uint8_t)) * n_index);
-  } else if ((max_num_bins - 1 > static_cast<int>(std::numeric_limits<uint8_t>::max()) &&
-              max_num_bins - 1 <= static_cast<int>(std::numeric_limits<uint16_t>::max())) &&
+  } else if ((MaxNumBinPerFeat() - 1 > static_cast<int>(std::numeric_limits<uint8_t>::max()) &&
+              MaxNumBinPerFeat() - 1 <= static_cast<int>(std::numeric_limits<uint16_t>::max())) &&
              isDense) {
     // compress dense index to uint16
     index.SetBinTypeSize(common::kUint16BinsTypeSize);
diff --git a/src/data/gradient_index.cu b/src/data/gradient_index.cu
index 42d935b3ca84..af5b0f67ba05 100644
--- a/src/data/gradient_index.cu
+++ b/src/data/gradient_index.cu
@@ -65,7 +65,7 @@ void GetRowPtrFromEllpack(Context const* ctx, EllpackPageImpl const* page,
 
 GHistIndexMatrix::GHistIndexMatrix(Context const* ctx, MetaInfo const& info,
                                    EllpackPage const& in_page, BatchParam const& p)
-    : max_num_bins{p.max_bin} {
+    : max_numeric_bins_per_feat{p.max_bin} {
   auto page = in_page.Impl();
   isDense_ = page->is_dense;
 
diff --git a/src/data/gradient_index.h b/src/data/gradient_index.h
index 10d9e770dc13..0fc0daf9dee0 100644
--- a/src/data/gradient_index.h
+++ b/src/data/gradient_index.h
@@ -133,11 +133,15 @@ class GHistIndexMatrix {
   std::vector<size_t> hit_count;
   /*! \brief The corresponding cuts */
   common::HistogramCuts cut;
-  /*! \brief max_bin for each feature. */
-  bst_bin_t max_num_bins;
+  /** \brief max_bin for each feature. */
+  bst_bin_t max_numeric_bins_per_feat;
   /*! \brief base row index for current page (used by external memory) */
   size_t base_rowid{0};
 
+  bst_bin_t MaxNumBinPerFeat() const {
+    return std::max(static_cast<bst_bin_t>(cut.MaxCategory() + 1), max_numeric_bins_per_feat);
+  }
+
   ~GHistIndexMatrix();
   /**
    * \brief Constrcutor for SimpleDMatrix.
@@ -160,7 +164,7 @@ class GHistIndexMatrix {
    * \brief Constructor for external memory.
    */
   GHistIndexMatrix(SparsePage const& page, common::Span<FeatureType const> ft,
-                   common::HistogramCuts const& cuts, int32_t max_bins_per_feat, bool is_dense,
+                   common::HistogramCuts cuts, int32_t max_bins_per_feat, bool is_dense,
                    double sparse_thresh, int32_t n_threads);
   GHistIndexMatrix();  // also for ext mem, empty ctor so that we can read the cache back.
 
diff --git a/src/data/gradient_index_format.cc b/src/data/gradient_index_format.cc
index 4b3fd0ea0f77..204157682a94 100644
--- a/src/data/gradient_index_format.cc
+++ b/src/data/gradient_index_format.cc
@@ -35,7 +35,7 @@ class GHistIndexRawFormat : public SparsePageFormat<GHistIndexMatrix> {
     if (!fi->Read(&page->hit_count)) {
       return false;
     }
-    if (!fi->Read(&page->max_num_bins)) {
+    if (!fi->Read(&page->max_numeric_bins_per_feat)) {
       return false;
     }
     if (!fi->Read(&page->base_rowid)) {
@@ -76,8 +76,8 @@ class GHistIndexRawFormat : public SparsePageFormat<GHistIndexMatrix> {
         page.hit_count.size() * sizeof(decltype(page.hit_count)::value_type) +
         sizeof(uint64_t);
     // max_bins, base row, is_dense
-    fo->Write(page.max_num_bins);
-    bytes += sizeof(page.max_num_bins);
+    fo->Write(page.max_numeric_bins_per_feat);
+    bytes += sizeof(page.max_numeric_bins_per_feat);
     fo->Write(page.base_rowid);
     bytes += sizeof(page.base_rowid);
     fo->Write(page.IsDense());
diff --git a/src/data/iterative_dmatrix.cc b/src/data/iterative_dmatrix.cc
index 19dd3490d040..317ea5b5d140 100644
--- a/src/data/iterative_dmatrix.cc
+++ b/src/data/iterative_dmatrix.cc
@@ -58,6 +58,13 @@ void GetCutsFromRef(std::shared_ptr<DMatrix> ref_, bst_feature_t n_features, Bat
     }
   };
   auto ellpack = [&]() {
+    // workaround ellpack being initialized from CPU.
+    if (p.gpu_id == Context::kCpuId) {
+      p.gpu_id = ref_->Ctx()->gpu_id;
+    }
+    if (p.gpu_id == Context::kCpuId) {
+      p.gpu_id = 0;
+    }
     for (auto const& page : ref_->GetBatches<EllpackPage>(p)) {
       GetCutsFromEllpack(page, p_cuts);
       break;
@@ -103,6 +110,7 @@ void IterativeDMatrix::InitFromCPU(DataIterHandle iter_handle, float missing,
       size_t n_threads = ctx_.Threads();
       size_t n_features = column_sizes.size();
       linalg::Tensor<size_t, 2> column_sizes_tloc({n_threads, n_features}, Context::kCpuId);
+      column_sizes_tloc.Data()->Fill(0);
       auto view = column_sizes_tloc.HostView();
       common::ParallelFor(value.Size(), n_threads, common::Sched::Static(256), [&](auto i) {
         auto const& line = value.GetLine(i);
@@ -172,9 +180,9 @@ void IterativeDMatrix::InitFromCPU(DataIterHandle iter_handle, float missing,
     size_t i = 0;
     while (iter.Next()) {
       if (!p_sketch) {
-        p_sketch.reset(new common::HostSketchContainer{batch_param_.max_bin,
-                                                       proxy->Info().feature_types.ConstHostSpan(),
-                                                       column_sizes, false, ctx_.Threads()});
+        p_sketch.reset(new common::HostSketchContainer{
+            batch_param_.max_bin, proxy->Info().feature_types.ConstHostSpan(), column_sizes,
+            !proxy->Info().group_ptr_.empty(), ctx_.Threads()});
       }
       HostAdapterDispatch(proxy, [&](auto const& batch) {
         proxy->Info().num_nonzero_ = batch_nnz[i];
diff --git a/src/data/proxy_dmatrix.cc b/src/data/proxy_dmatrix.cc
index fc36f75f28ac..ba75dec19d83 100644
--- a/src/data/proxy_dmatrix.cc
+++ b/src/data/proxy_dmatrix.cc
@@ -15,6 +15,15 @@ void DMatrixProxy::SetArrayData(char const *c_interface) {
   this->ctx_.gpu_id = Context::kCpuId;
 }
 
+void DMatrixProxy::SetDenseData(const float *data, size_t num_rows,
+                                size_t num_features) {
+  std::shared_ptr<xgboost::data::DenseAdapter> adapter{new xgboost::data::DenseAdapter(data, num_rows, num_features)};
+  this->batch_ = adapter;
+  this->Info().num_col_ = adapter->NumColumns();
+  this->Info().num_row_ = adapter->NumRows();
+  this->ctx_.gpu_id = Context::kCpuId;
+}
+
 void DMatrixProxy::SetCSRData(char const *c_indptr, char const *c_indices,
                               char const *c_values, bst_feature_t n_features, bool on_host) {
   CHECK(on_host) << "Not implemented on device.";
diff --git a/src/data/proxy_dmatrix.h b/src/data/proxy_dmatrix.h
index 8375c7c8d6c1..4e8601b84a8b 100644
--- a/src/data/proxy_dmatrix.h
+++ b/src/data/proxy_dmatrix.h
@@ -70,6 +70,8 @@ class DMatrixProxy : public DMatrix {
   }
 
   void SetArrayData(char const* c_interface);
+  void SetDenseData(const float *data,size_t num_rows,
+                    size_t num_features);
   void SetCSRData(char const *c_indptr, char const *c_indices,
                   char const *c_values, bst_feature_t n_features,
                   bool on_host);
diff --git a/src/data/simple_dmatrix.cc b/src/data/simple_dmatrix.cc
index 4679ef543ea2..c2a69a204db0 100644
--- a/src/data/simple_dmatrix.cc
+++ b/src/data/simple_dmatrix.cc
@@ -42,6 +42,7 @@ DMatrix* SimpleDMatrix::Slice(common::Span<int32_t const> ridxs) {
     out->Info() = this->Info().Slice(ridxs);
     out->Info().num_nonzero_ = h_offset.back();
   }
+  out->ctx_ = this->ctx_;
   return out;
 }
 
diff --git a/src/gbm/gbtree.cc b/src/gbm/gbtree.cc
index e9e888a98e46..92b54625d150 100644
--- a/src/gbm/gbtree.cc
+++ b/src/gbm/gbtree.cc
@@ -28,6 +28,7 @@
 #include "xgboost/logging.h"
 #include "xgboost/objective.h"
 #include "xgboost/predictor.h"
+#include "xgboost/string_view.h"
 #include "xgboost/tree_updater.h"
 
 namespace xgboost {
@@ -395,23 +396,36 @@ void GBTree::LoadConfig(Json const& in) {
   tparam_.process_type = TreeProcessType::kDefault;
   int32_t const n_gpus = xgboost::common::AllVisibleGPUs();
   if (n_gpus == 0 && tparam_.predictor == PredictorType::kGPUPredictor) {
-    LOG(WARNING)
-        << "Loading from a raw memory buffer on CPU only machine.  "
-           "Changing predictor to auto.";
+    LOG(WARNING) << "Loading from a raw memory buffer on CPU only machine.  "
+                    "Changing predictor to auto.";
     tparam_.UpdateAllowUnknown(Args{{"predictor", "auto"}});
   }
+
+  auto msg = StringView{
+      R"(
+  Loading from a raw memory buffer (like pickle in Python, RDS in R) on a CPU-only
+  machine. Consider using `save_model/load_model` instead. See:
+
+    https://xgboost.readthedocs.io/en/latest/tutorials/saving_model.html
+
+  for more details about differences between saving model and serializing.)"};
+
   if (n_gpus == 0 && tparam_.tree_method == TreeMethod::kGPUHist) {
     tparam_.UpdateAllowUnknown(Args{{"tree_method", "hist"}});
-    LOG(WARNING)
-        << "Loading from a raw memory buffer on CPU only machine.  "
-           "Changing tree_method to hist.";
+    LOG(WARNING) << msg << "  Changing `tree_method` to `hist`.";
   }
 
   auto const& j_updaters = get<Object const>(in["updater"]);
   updaters_.clear();
+
   for (auto const& kv : j_updaters) {
-    std::unique_ptr<TreeUpdater> up(
-        TreeUpdater::Create(kv.first, ctx_, model_.learner_model_param->task));
+    auto name = kv.first;
+    if (n_gpus == 0 && name == "grow_gpu_hist") {
+      name = "grow_quantile_histmaker";
+      LOG(WARNING) << "Changing updater from `grow_gpu_hist` to `grow_quantile_histmaker`.";
+    }
+    std::unique_ptr<TreeUpdater> up{
+        TreeUpdater::Create(name, ctx_, model_.learner_model_param->task)};
     up->LoadConfig(kv.second);
     updaters_.push_back(std::move(up));
   }
diff --git a/src/objective/adaptive.cu b/src/objective/adaptive.cu
index aa01370b05fa..f77f4a4a858b 100644
--- a/src/objective/adaptive.cu
+++ b/src/objective/adaptive.cu
@@ -67,6 +67,10 @@ void EncodeTreeLeafDevice(Context const* ctx, common::Span<bst_node_t const> pos
   auto pinned = pinned_pool.GetSpan<char>(sizeof(size_t) + sizeof(bst_node_t));
   dh::CUDAStream copy_stream;
   size_t* h_num_runs = reinterpret_cast<size_t*>(pinned.subspan(0, sizeof(size_t)).data());
+
+  dh::CUDAEvent e;
+  e.Record(dh::DefaultStream());
+  copy_stream.View().Wait(e);
   // flag for whether there's ignored position
   bst_node_t* h_first_unique =
       reinterpret_cast<bst_node_t*>(pinned.subspan(sizeof(size_t), sizeof(bst_node_t)).data());
diff --git a/src/predictor/cpu_predictor.cc b/src/predictor/cpu_predictor.cc
index 444d1b089d21..a2f3cb863393 100644
--- a/src/predictor/cpu_predictor.cc
+++ b/src/predictor/cpu_predictor.cc
@@ -396,8 +396,9 @@ class CPUPredictor : public Predictor {
   bool InplacePredict(std::shared_ptr<DMatrix> p_m, const gbm::GBTreeModel &model, float missing,
                       PredictionCacheEntry *out_preds, uint32_t tree_begin,
                       unsigned tree_end) const override {
+    //fprintf (stdout, "We are in cpu_predictor");
     auto proxy = dynamic_cast<data::DMatrixProxy *>(p_m.get());
-    CHECK(proxy)<< "Inplace predict accepts only DMatrixProxy as input.";
+    //auto proxy = new std::shared_ptr<xgboost::DMatrix>(new xgboost::data::DMatrixProxy);
     auto x = proxy->Adapter();
     if (x.type() == typeid(std::shared_ptr<data::DenseAdapter>)) {
       this->DispatchedInplacePredict<data::DenseAdapter, kBlockOfRowsSize>(
diff --git a/src/predictor/predict_fn.h b/src/predictor/predict_fn.h
index 7ce474023e8a..5d0c175fcf65 100644
--- a/src/predictor/predict_fn.h
+++ b/src/predictor/predict_fn.h
@@ -18,9 +18,7 @@ inline XGBOOST_DEVICE bst_node_t GetNextNode(const RegTree::Node &node, const bs
     if (has_categorical && common::IsCat(cats.split_type, nid)) {
       auto node_categories =
           cats.categories.subspan(cats.node_ptr[nid].beg, cats.node_ptr[nid].size);
-      return common::Decision<true>(node_categories, fvalue, node.DefaultLeft())
-                 ? node.LeftChild()
-                 : node.RightChild();
+      return common::Decision(node_categories, fvalue) ? node.LeftChild() : node.RightChild();
     } else {
       return node.LeftChild() + !(fvalue < node.SplitCond());
     }
diff --git a/src/tree/gpu_hist/evaluate_splits.cu b/src/tree/gpu_hist/evaluate_splits.cu
index e471c8d361f5..781fff92aef8 100644
--- a/src/tree/gpu_hist/evaluate_splits.cu
+++ b/src/tree/gpu_hist/evaluate_splits.cu
@@ -248,8 +248,10 @@ class EvaluateSplitAgent {
 
 template <int kBlockSize>
 __global__ __launch_bounds__(kBlockSize) void EvaluateSplitsKernel(
-    bst_feature_t number_active_features, common::Span<const EvaluateSplitInputs> d_inputs,
-    const EvaluateSplitSharedInputs shared_inputs, common::Span<bst_feature_t> sorted_idx,
+    bst_feature_t max_active_features,
+    common::Span<const EvaluateSplitInputs> d_inputs,
+    const EvaluateSplitSharedInputs shared_inputs,
+    common::Span<bst_feature_t> sorted_idx,
     const TreeEvaluator::SplitEvaluator<GPUTrainingParam> evaluator,
     common::Span<DeviceSplitCandidate> out_candidates) {
   // Aligned && shared storage for best_split
@@ -263,11 +265,15 @@ __global__ __launch_bounds__(kBlockSize) void EvaluateSplitsKernel(
   __syncthreads();
 
   // Allocate blocks to one feature of one node
-  const auto input_idx = blockIdx.x / number_active_features;
+  const auto input_idx = blockIdx.x / max_active_features;
   const EvaluateSplitInputs &inputs = d_inputs[input_idx];
   // One block for each feature. Features are sampled, so fidx != blockIdx.x
-
-  int fidx = inputs.feature_set[blockIdx.x % number_active_features];
+  // Some blocks may not have any feature to work on, simply return
+  int feature_offset = blockIdx.x % max_active_features;
+  if (feature_offset >= inputs.feature_set.size()) {
+    return;
+  }
+  int fidx = inputs.feature_set[feature_offset];
 
   using AgentT = EvaluateSplitAgent<kBlockSize>;
   __shared__ typename AgentT::TempStorage temp_storage;
@@ -338,7 +344,8 @@ __device__ void SetCategoricalSplit(const EvaluateSplitSharedInputs &shared_inpu
 }
 
 void GPUHistEvaluator::LaunchEvaluateSplits(
-    bst_feature_t number_active_features, common::Span<const EvaluateSplitInputs> d_inputs,
+    bst_feature_t max_active_features,
+    common::Span<const EvaluateSplitInputs> d_inputs,
     EvaluateSplitSharedInputs shared_inputs,
     TreeEvaluator::SplitEvaluator<GPUTrainingParam> evaluator,
     common::Span<DeviceSplitCandidate> out_splits) {
@@ -346,20 +353,25 @@ void GPUHistEvaluator::LaunchEvaluateSplits(
     this->SortHistogram(d_inputs, shared_inputs, evaluator);
   }
 
-  size_t combined_num_features = number_active_features * d_inputs.size();
-  dh::TemporaryArray<DeviceSplitCandidate> feature_best_splits(combined_num_features);
+  size_t combined_num_features = max_active_features * d_inputs.size();
+  dh::TemporaryArray<DeviceSplitCandidate> feature_best_splits(
+      combined_num_features, DeviceSplitCandidate());
 
   // One block for each feature
   uint32_t constexpr kBlockThreads = 32;
-  dh::LaunchKernel {static_cast<uint32_t>(combined_num_features), kBlockThreads, 0}(
-      EvaluateSplitsKernel<kBlockThreads>, number_active_features, d_inputs,
-      shared_inputs, this->SortedIdx(d_inputs.size(), shared_inputs.feature_values.size()),
+  dh::LaunchKernel{static_cast<uint32_t>(combined_num_features), kBlockThreads,
+                   0}(
+      EvaluateSplitsKernel<kBlockThreads>, max_active_features, d_inputs,
+      shared_inputs,
+      this->SortedIdx(d_inputs.size(), shared_inputs.feature_values.size()),
       evaluator, dh::ToSpan(feature_best_splits));
 
   // Reduce to get best candidate for left and right child over all features
-  auto reduce_offset = dh::MakeTransformIterator<size_t>(
-      thrust::make_counting_iterator(0llu),
-      [=] __device__(size_t idx) -> size_t { return idx * number_active_features; });
+  auto reduce_offset =
+      dh::MakeTransformIterator<size_t>(thrust::make_counting_iterator(0llu),
+                                        [=] __device__(size_t idx) -> size_t {
+                                          return idx * max_active_features;
+                                        });
   size_t temp_storage_bytes = 0;
   auto num_segments = out_splits.size();
   cub::DeviceSegmentedReduce::Sum(nullptr, temp_storage_bytes, feature_best_splits.data(),
@@ -386,15 +398,16 @@ void GPUHistEvaluator::CopyToHost(const std::vector<bst_node_t> &nidx) {
 }
 
 void GPUHistEvaluator::EvaluateSplits(
-    const std::vector<bst_node_t> &nidx, bst_feature_t number_active_features,
-    common::Span<const EvaluateSplitInputs> d_inputs, EvaluateSplitSharedInputs shared_inputs,
+    const std::vector<bst_node_t> &nidx, bst_feature_t max_active_features,
+    common::Span<const EvaluateSplitInputs> d_inputs,
+    EvaluateSplitSharedInputs shared_inputs,
     common::Span<GPUExpandEntry> out_entries) {
   auto evaluator = this->tree_evaluator_.template GetEvaluator<GPUTrainingParam>();
 
   dh::TemporaryArray<DeviceSplitCandidate> splits_out_storage(d_inputs.size());
   auto out_splits = dh::ToSpan(splits_out_storage);
-  this->LaunchEvaluateSplits(number_active_features, d_inputs, shared_inputs, evaluator,
-                             out_splits);
+  this->LaunchEvaluateSplits(max_active_features, d_inputs, shared_inputs,
+                             evaluator, out_splits);
 
   auto d_sorted_idx = this->SortedIdx(d_inputs.size(), shared_inputs.feature_values.size());
   auto d_entries = out_entries;
diff --git a/src/tree/gpu_hist/evaluate_splits.cuh b/src/tree/gpu_hist/evaluate_splits.cuh
index 2da207e79104..0b44f31aa5c0 100644
--- a/src/tree/gpu_hist/evaluate_splits.cuh
+++ b/src/tree/gpu_hist/evaluate_splits.cuh
@@ -3,10 +3,10 @@
  */
 #ifndef EVALUATE_SPLITS_CUH_
 #define EVALUATE_SPLITS_CUH_
-#include <thrust/system/cuda/experimental/pinned_allocator.h>
 #include <xgboost/span.h>
 
 #include "../../common/categorical.h"
+#include "../../common/cuda_pinned_allocator.h"
 #include "../split_evaluator.h"
 #include "../updater_gpu_common.cuh"
 #include "expand_entry.cuh"
@@ -57,7 +57,7 @@ struct CatAccessor {
 class GPUHistEvaluator {
   using CatST = common::CatBitField::value_type;  // categorical storage type
   // use pinned memory to stage the categories, used for sort based splits.
-  using Alloc = thrust::system::cuda::experimental::pinned_allocator<CatST>;
+  using Alloc = xgboost::common::cuda::pinned_allocator<CatST>;
 
  private:
   TreeEvaluator tree_evaluator_;
@@ -170,13 +170,18 @@ class GPUHistEvaluator {
       TreeEvaluator::SplitEvaluator<GPUTrainingParam> evaluator);
 
   // impl of evaluate splits, contains CUDA kernels so it's public
-  void LaunchEvaluateSplits(bst_feature_t number_active_features,common::Span<const EvaluateSplitInputs> d_inputs,EvaluateSplitSharedInputs shared_inputs,
-                      TreeEvaluator::SplitEvaluator<GPUTrainingParam> evaluator,
-                      common::Span<DeviceSplitCandidate> out_splits);
+  void LaunchEvaluateSplits(
+      bst_feature_t max_active_features,
+      common::Span<const EvaluateSplitInputs> d_inputs,
+      EvaluateSplitSharedInputs shared_inputs,
+      TreeEvaluator::SplitEvaluator<GPUTrainingParam> evaluator,
+      common::Span<DeviceSplitCandidate> out_splits);
   /**
    * \brief Evaluate splits for left and right nodes.
    */
-  void EvaluateSplits(const std::vector<bst_node_t> &nidx,bst_feature_t number_active_features,common::Span<const EvaluateSplitInputs> d_inputs,
+  void EvaluateSplits(const std::vector<bst_node_t> &nidx,
+                      bst_feature_t max_active_features,
+                      common::Span<const EvaluateSplitInputs> d_inputs,
                       EvaluateSplitSharedInputs shared_inputs,
                       common::Span<GPUExpandEntry> out_splits);
   /**
diff --git a/src/tree/updater_gpu_hist.cu b/src/tree/updater_gpu_hist.cu
index b3b3004a2cb3..8625395c2ae4 100644
--- a/src/tree/updater_gpu_hist.cu
+++ b/src/tree/updater_gpu_hist.cu
@@ -188,7 +188,8 @@ struct GPUHistMakerDevice {
   common::Span<GradientPair> gpair;
 
   dh::device_vector<int> monotone_constraints;
-  dh::device_vector<float> update_predictions;
+  // node idx for each sample
+  dh::device_vector<bst_node_t> positions;
 
   TrainParam param;
 
@@ -305,6 +306,8 @@ struct GPUHistMakerDevice {
         matrix.is_dense
     };
     dh::TemporaryArray<GPUExpandEntry> entries(2 * candidates.size());
+    // Store the feature set ptrs so they dont go out of scope before the kernel is called
+    std::vector<std::shared_ptr<HostDeviceVector<bst_feature_t>>> feature_sets;
     for (size_t i = 0; i < candidates.size(); i++) {
       auto candidate = candidates.at(i);
       int left_nidx = tree[candidate.nid].LeftChild();
@@ -313,29 +316,34 @@ struct GPUHistMakerDevice {
       nidx[i * 2 + 1] = right_nidx;
       auto left_sampled_features = column_sampler.GetFeatureSet(tree.GetDepth(left_nidx));
       left_sampled_features->SetDevice(ctx_->gpu_id);
+      feature_sets.emplace_back(left_sampled_features);
       common::Span<bst_feature_t> left_feature_set =
           interaction_constraints.Query(left_sampled_features->DeviceSpan(), left_nidx);
       auto right_sampled_features = column_sampler.GetFeatureSet(tree.GetDepth(right_nidx));
       right_sampled_features->SetDevice(ctx_->gpu_id);
+      feature_sets.emplace_back(right_sampled_features);
       common::Span<bst_feature_t> right_feature_set =
-          interaction_constraints.Query(right_sampled_features->DeviceSpan(), left_nidx);
-      h_node_inputs[i * 2] = {left_nidx, candidate.depth + 1, candidate.split.left_sum,
-                              left_feature_set, hist.GetNodeHistogram(left_nidx)};
-      h_node_inputs[i * 2 + 1] = {right_nidx, candidate.depth + 1, candidate.split.right_sum,
-                                  right_feature_set, hist.GetNodeHistogram(right_nidx)};
+          interaction_constraints.Query(right_sampled_features->DeviceSpan(),
+                                        right_nidx);
+      h_node_inputs[i * 2] = {left_nidx, candidate.depth + 1,
+                              candidate.split.left_sum, left_feature_set,
+                              hist.GetNodeHistogram(left_nidx)};
+      h_node_inputs[i * 2 + 1] = {right_nidx, candidate.depth + 1,
+                                  candidate.split.right_sum, right_feature_set,
+                                  hist.GetNodeHistogram(right_nidx)};
     }
-    bst_feature_t number_active_features = h_node_inputs[0].feature_set.size();
+    bst_feature_t max_active_features = 0;
     for (auto input : h_node_inputs) {
-      CHECK_EQ(input.feature_set.size(), number_active_features)
-          << "Current implementation assumes that the number of active features "
-             "(after sampling) in any node is the same";
+      max_active_features = std::max(max_active_features,
+                                     bst_feature_t(input.feature_set.size()));
     }
-    dh::safe_cuda(cudaMemcpyAsync(d_node_inputs.data().get(), h_node_inputs.data(),
-                                  h_node_inputs.size() * sizeof(EvaluateSplitInputs),
-                                  cudaMemcpyDefault));
+    dh::safe_cuda(cudaMemcpyAsync(
+        d_node_inputs.data().get(), h_node_inputs.data(),
+        h_node_inputs.size() * sizeof(EvaluateSplitInputs), cudaMemcpyDefault));
 
-    this->evaluator_.EvaluateSplits(nidx, number_active_features, dh::ToSpan(d_node_inputs),
-                                    shared_inputs, dh::ToSpan(entries));
+    this->evaluator_.EvaluateSplits(nidx, max_active_features,
+                                    dh::ToSpan(d_node_inputs), shared_inputs,
+                                    dh::ToSpan(entries));
     dh::safe_cuda(cudaMemcpyAsync(pinned_candidates_out.data(),
                                   entries.data().get(), sizeof(GPUExpandEntry) * entries.size(),
                                   cudaMemcpyDeviceToHost));
@@ -403,8 +411,7 @@ struct GPUHistMakerDevice {
             go_left = data.split_node.DefaultLeft();
           } else {
             if (data.split_type == FeatureType::kCategorical) {
-              go_left = common::Decision<false>(data.node_cats.Bits(), cut_value,
-                                                data.split_node.DefaultLeft());
+              go_left = common::Decision(data.node_cats.Bits(), cut_value);
             } else {
               go_left = cut_value <= data.split_node.SplitCond();
             }
@@ -424,7 +431,7 @@ struct GPUHistMakerDevice {
         LOG(FATAL) << "Current objective function can not be used with external memory.";
       }
       p_out_position->Resize(0);
-      update_predictions.clear();
+      positions.clear();
       return;
     }
 
@@ -459,8 +466,6 @@ struct GPUHistMakerDevice {
                               HostDeviceVector<bst_node_t>* p_out_position) {
     auto d_matrix = page->GetDeviceAccessor(ctx_->gpu_id);
     auto d_gpair = this->gpair;
-    update_predictions.resize(row_partitioner->GetRows().size());
-    auto d_update_predictions = dh::ToSpan(update_predictions);
     p_out_position->SetDevice(ctx_->gpu_id);
     p_out_position->Resize(row_partitioner->GetRows().size());
 
@@ -481,7 +486,7 @@ struct GPUHistMakerDevice {
           if (common::IsCat(d_feature_types, position)) {
             auto node_cats = categories.subspan(categories_segments[position].beg,
                                                 categories_segments[position].size);
-            go_left = common::Decision<false>(node_cats, element, node.DefaultLeft());
+            go_left = common::Decision(node_cats, element);
           } else {
             go_left = element <= node.SplitCond();
           }
@@ -495,32 +500,45 @@ struct GPUHistMakerDevice {
         node = d_nodes[position];
       }
 
-      d_update_predictions[row_id] = node.LeafValue();
       return position;
     };  // NOLINT
 
     auto d_out_position = p_out_position->DeviceSpan();
     row_partitioner->FinalisePosition(d_out_position, new_position_op);
 
+    auto s_position = p_out_position->ConstDeviceSpan();
+    positions.resize(s_position.size());
+    dh::safe_cuda(cudaMemcpyAsync(positions.data().get(), s_position.data(),
+                                  s_position.size_bytes(), cudaMemcpyDeviceToDevice));
+
     dh::LaunchN(row_partitioner->GetRows().size(), [=] __device__(size_t idx) {
       bst_node_t position = d_out_position[idx];
-      d_update_predictions[idx] = d_nodes[position].LeafValue();
       bool is_row_sampled = d_gpair[idx].GetHess() - .0f == 0.f;
       d_out_position[idx] = is_row_sampled ? ~position : position;
     });
   }
 
   bool UpdatePredictionCache(linalg::VectorView<float> out_preds_d, RegTree const* p_tree) {
-    if (update_predictions.empty()) {
+    if (positions.empty()) {
       return false;
     }
+
     CHECK(p_tree);
     dh::safe_cuda(cudaSetDevice(ctx_->gpu_id));
     CHECK_EQ(out_preds_d.DeviceIdx(), ctx_->gpu_id);
-    auto d_update_predictions = dh::ToSpan(update_predictions);
-    CHECK_EQ(out_preds_d.Size(), d_update_predictions.size());
-    dh::LaunchN(out_preds_d.Size(), [=] XGBOOST_DEVICE(size_t idx) mutable {
-      out_preds_d(idx) += d_update_predictions[idx];
+
+    auto d_position = dh::ToSpan(positions);
+    CHECK_EQ(out_preds_d.Size(), d_position.size());
+
+    auto const& h_nodes = p_tree->GetNodes();
+    dh::caching_device_vector<RegTree::Node> nodes(h_nodes.size());
+    dh::safe_cuda(cudaMemcpyAsync(nodes.data().get(), h_nodes.data(),
+                                  h_nodes.size() * sizeof(RegTree::Node), cudaMemcpyHostToDevice));
+    auto d_nodes = dh::ToSpan(nodes);
+    dh::LaunchN(d_position.size(), [=] XGBOOST_DEVICE(std::size_t idx) mutable {
+      bst_node_t nidx = d_position[idx];
+      auto weight = d_nodes[nidx].LeafValue();
+      out_preds_d(idx) += weight;
     });
     return true;
   }
@@ -863,6 +881,7 @@ class GPUHistMaker : public TreeUpdater {
   std::unique_ptr<GPUHistMakerDevice<GradientSumT>> maker;  // NOLINT
 
   char const* Name() const override { return "grow_gpu_hist"; }
+  bool HasNodePosition() const override { return true; }
 
  private:
   bool initialised_{false};
diff --git a/tests/buildkite/build-containers.sh b/tests/buildkite/build-containers.sh
index 41a13eaea5fb..899976a7ddf7 100755
--- a/tests/buildkite/build-containers.sh
+++ b/tests/buildkite/build-containers.sh
@@ -23,10 +23,15 @@ case "${container}" in
   gpu|rmm)
     BUILD_ARGS="$BUILD_ARGS --build-arg CUDA_VERSION_ARG=$CUDA_VERSION"
     BUILD_ARGS="$BUILD_ARGS --build-arg RAPIDS_VERSION_ARG=$RAPIDS_VERSION"
+    if [[ $container == "rmm" ]]
+    then
+      BUILD_ARGS="$BUILD_ARGS --build-arg NCCL_VERSION_ARG=$NCCL_VERSION"
+    fi
     ;;
 
   gpu_build_centos7|jvm_gpu_build)
     BUILD_ARGS="$BUILD_ARGS --build-arg CUDA_VERSION_ARG=$CUDA_VERSION"
+    BUILD_ARGS="$BUILD_ARGS --build-arg NCCL_VERSION_ARG=$NCCL_VERSION"
     ;;
 
   *)
diff --git a/tests/buildkite/build-cuda-with-rmm.sh b/tests/buildkite/build-cuda-with-rmm.sh
index ae704ce662ab..f474f318b675 100755
--- a/tests/buildkite/build-cuda-with-rmm.sh
+++ b/tests/buildkite/build-cuda-with-rmm.sh
@@ -15,7 +15,8 @@ fi
 
 command_wrapper="tests/ci_build/ci_build.sh rmm docker --build-arg "`
                 `"CUDA_VERSION_ARG=$CUDA_VERSION --build-arg "`
-                `"RAPIDS_VERSION_ARG=$RAPIDS_VERSION"
+                `"RAPIDS_VERSION_ARG=$RAPIDS_VERSION --build-arg "`
+                `"NCCL_VERSION_ARG=$NCCL_VERSION"
 
 echo "--- Build libxgboost from the source"
 $command_wrapper tests/ci_build/build_via_cmake.sh --conda-env=gpu_test -DUSE_CUDA=ON \
diff --git a/tests/buildkite/build-cuda.sh b/tests/buildkite/build-cuda.sh
index a50963f7c7fc..b25345b1bbb1 100755
--- a/tests/buildkite/build-cuda.sh
+++ b/tests/buildkite/build-cuda.sh
@@ -16,7 +16,8 @@ else
 fi
 
 command_wrapper="tests/ci_build/ci_build.sh gpu_build_centos7 docker --build-arg "`
-                `"CUDA_VERSION_ARG=$CUDA_VERSION"
+                `"CUDA_VERSION_ARG=$CUDA_VERSION --build-arg "`
+                `"NCCL_VERSION_ARG=$NCCL_VERSION"
 
 echo "--- Build libxgboost from the source"
 $command_wrapper tests/ci_build/prune_libnccl.sh
diff --git a/tests/buildkite/build-jvm-packages-gpu.sh b/tests/buildkite/build-jvm-packages-gpu.sh
index 30e73eb37386..6a9a29cb39fb 100755
--- a/tests/buildkite/build-jvm-packages-gpu.sh
+++ b/tests/buildkite/build-jvm-packages-gpu.sh
@@ -14,5 +14,7 @@ else
 fi
 
 tests/ci_build/ci_build.sh jvm_gpu_build nvidia-docker \
-  --build-arg CUDA_VERSION_ARG=${CUDA_VERSION} tests/ci_build/build_jvm_packages.sh \
+  --build-arg CUDA_VERSION_ARG=${CUDA_VERSION} \
+  --build-arg NCCL_VERSION_ARG=${NCCL_VERSION} \
+  tests/ci_build/build_jvm_packages.sh \
   ${SPARK_VERSION} -Duse.cuda=ON ${arch_flag}
diff --git a/tests/buildkite/build-win64-gpu.ps1 b/tests/buildkite/build-win64-gpu.ps1
index 6ee723abbec0..05d7aefb9048 100644
--- a/tests/buildkite/build-win64-gpu.ps1
+++ b/tests/buildkite/build-win64-gpu.ps1
@@ -12,10 +12,10 @@ if ( $is_release_branch -eq 0 ) {
 }
 mkdir build
 cd build
-cmake .. -G"Visual Studio 15 2017 Win64" -DUSE_CUDA=ON -DCMAKE_VERBOSE_MAKEFILE=ON `
-  -DGOOGLE_TEST=ON -DUSE_DMLC_GTEST=ON -DCMAKE_UNITY_BUILD=ON ${arch_flag}
+cmake .. -G"Visual Studio 17 2022" -A x64 -DUSE_CUDA=ON -DCMAKE_VERBOSE_MAKEFILE=ON `
+  -DGOOGLE_TEST=ON -DUSE_DMLC_GTEST=ON ${arch_flag}
 $msbuild = -join @(
-  "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community\\MSBuild\\15.0"
+  "C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\MSBuild\\Current"
   "\\Bin\\MSBuild.exe"
 )
 & $msbuild xgboost.sln /m /p:Configuration=Release /nodeReuse:false
diff --git a/tests/buildkite/conftest.sh b/tests/buildkite/conftest.sh
index 30ef4aeab3bc..cf9270c1162c 100755
--- a/tests/buildkite/conftest.sh
+++ b/tests/buildkite/conftest.sh
@@ -22,9 +22,10 @@ function set_buildkite_env_vars_in_container {
 
 set -x
 
-CUDA_VERSION=11.0.3
-RAPIDS_VERSION=22.10
-SPARK_VERSION=3.0.1
+CUDA_VERSION=11.8.0
+NCCL_VERSION=2.16.5-1
+RAPIDS_VERSION=23.02
+SPARK_VERSION=3.1.1
 JDK_VERSION=8
 
 if [[ -z ${BUILDKITE:-} ]]
diff --git a/tests/buildkite/deploy-jvm-packages.sh b/tests/buildkite/deploy-jvm-packages.sh
index 6ae5a719db47..a3410b294bd6 100755
--- a/tests/buildkite/deploy-jvm-packages.sh
+++ b/tests/buildkite/deploy-jvm-packages.sh
@@ -9,5 +9,6 @@ then
   echo "--- Deploy JVM packages to xgboost-maven-repo S3 repo"
   tests/ci_build/ci_build.sh jvm_gpu_build docker \
     --build-arg CUDA_VERSION_ARG=${CUDA_VERSION} \
+    --build-arg NCCL_VERSION_ARG=${NCCL_VERSION} \
     tests/ci_build/deploy_jvm_packages.sh ${SPARK_VERSION}
 fi
diff --git a/tests/buildkite/infrastructure/aws-stack-creator/create_stack.py b/tests/buildkite/infrastructure/aws-stack-creator/create_stack.py
index b9409de4cdcf..4277eed53318 100644
--- a/tests/buildkite/infrastructure/aws-stack-creator/create_stack.py
+++ b/tests/buildkite/infrastructure/aws-stack-creator/create_stack.py
@@ -2,12 +2,16 @@
 import copy
 import os
 import re
+import sys
 
 import boto3
 import botocore
 from metadata import AMI_ID, COMMON_STACK_PARAMS, STACK_PARAMS
 
 current_dir = os.path.dirname(__file__)
+sys.path.append(os.path.join(current_dir, ".."))
+
+from common_blocks.utils import create_or_update_stack, wait
 
 TEMPLATE_URL = "https://s3.amazonaws.com/buildkite-aws-stack/latest/aws-stack.yml"
 
@@ -68,72 +72,7 @@ def get_full_stack_id(stack_id):
     return f"buildkite-{stack_id}-autoscaling-group"
 
 
-def stack_exists(args, *, stack_name):
-    client = boto3.client("cloudformation", region_name=args.aws_region)
-    waiter = client.get_waiter("stack_exists")
-    try:
-        waiter.wait(StackName=stack_name, WaiterConfig={"MaxAttempts": 1})
-        return True
-    except botocore.exceptions.WaiterError as e:
-        return False
-
-
-def create_or_update_stack(
-    args, *, stack_name, template_url=None, template_body=None, params=None
-):
-    kwargs = {
-        "StackName": stack_name,
-        "Capabilities": [
-            "CAPABILITY_IAM",
-            "CAPABILITY_NAMED_IAM",
-            "CAPABILITY_AUTO_EXPAND",
-        ],
-    }
-    if template_url:
-        kwargs["TemplateURL"] = template_url
-    if template_body:
-        kwargs["TemplateBody"] = template_body
-    if params:
-        kwargs["Parameters"] = params
-
-    client = boto3.client("cloudformation", region_name=args.aws_region)
-
-    if stack_exists(args, stack_name=stack_name):
-        print(f"Stack {stack_name} already exists. Updating...")
-        try:
-            response = client.update_stack(**kwargs)
-            return {"StackName": stack_name, "Action": "update"}
-        except botocore.exceptions.ClientError as e:
-            if e.response["Error"]["Code"] == "ValidationError" and re.search(
-                "No updates are to be performed", e.response["Error"]["Message"]
-            ):
-                print(f"No update was made to {stack_name}")
-                return {"StackName": stack_name, "Action": "noop"}
-            else:
-                raise e
-    else:
-        kwargs.update({"OnFailure": "ROLLBACK", "EnableTerminationProtection": False})
-        response = client.create_stack(**kwargs)
-        return {"StackName": stack_name, "Action": "create"}
-
-
-def wait(promise):
-    client = boto3.client("cloudformation", region_name=args.aws_region)
-    stack_name = promise["StackName"]
-    print(f"Waiting for {stack_name}...")
-    if promise["Action"] == "create":
-        waiter = client.get_waiter("stack_create_complete")
-        waiter.wait(StackName=stack_name)
-        print(f"Finished creating stack {stack_name}")
-    elif promise["Action"] == "update":
-        waiter = client.get_waiter("stack_update_complete")
-        waiter.wait(StackName=stack_name)
-        print(f"Finished updating stack {stack_name}")
-    elif promise["Action"] != "noop":
-        raise ValueError(f"Invalid promise {promise}")
-
-
-def create_agent_iam_policy(args):
+def create_agent_iam_policy(args, *, client):
     policy_stack_name = "buildkite-agent-iam-policy"
     print(f"Creating stack {policy_stack_name} for agent IAM policy...")
     with open(
@@ -142,9 +81,9 @@ def create_agent_iam_policy(args):
     ) as f:
         policy_template = f.read()
     promise = create_or_update_stack(
-        args, stack_name=policy_stack_name, template_body=policy_template
+        args, client=client, stack_name=policy_stack_name, template_body=policy_template
     )
-    wait(promise)
+    wait(promise, client=client)
 
     cf = boto3.resource("cloudformation", region_name=args.aws_region)
     policy = cf.StackResource(policy_stack_name, "BuildkiteAgentManagedPolicy")
@@ -152,10 +91,10 @@ def create_agent_iam_policy(args):
 
 
 def main(args):
-    agent_iam_policy = create_agent_iam_policy(args)
-
     client = boto3.client("cloudformation", region_name=args.aws_region)
 
+    agent_iam_policy = create_agent_iam_policy(args, client=client)
+
     promises = []
 
     for stack_id in AMI_ID:
@@ -167,13 +106,17 @@ def main(args):
         )
 
         promise = create_or_update_stack(
-            args, stack_name=stack_id_full, template_url=TEMPLATE_URL, params=params
+            args,
+            client=client,
+            stack_name=stack_id_full,
+            template_url=TEMPLATE_URL,
+            params=params,
         )
         promises.append(promise)
         print(f"CI stack {stack_id_full} is in progress in the background")
 
     for promise in promises:
-        wait(promise)
+        wait(promise, client=client)
 
 
 if __name__ == "__main__":
diff --git a/tests/buildkite/infrastructure/aws-stack-creator/metadata.py b/tests/buildkite/infrastructure/aws-stack-creator/metadata.py
index edb4cc036f9c..30aa20a09500 100644
--- a/tests/buildkite/infrastructure/aws-stack-creator/metadata.py
+++ b/tests/buildkite/infrastructure/aws-stack-creator/metadata.py
@@ -1,27 +1,27 @@
 AMI_ID = {
     # Managed by XGBoost team
     "linux-amd64-gpu": {
-        "us-west-2": "ami-00ed92bd37f77bc33",
+        "us-west-2": "ami-094271bed4788ddb5",
     },
     "linux-amd64-mgpu": {
-        "us-west-2": "ami-00ed92bd37f77bc33",
+        "us-west-2": "ami-094271bed4788ddb5",
     },
     "windows-gpu": {
-        "us-west-2": "ami-0a1a2ea551a07ad5f",
+        "us-west-2": "ami-0839681594a1d7627",
     },
     "windows-cpu": {
-        "us-west-2": "ami-0a1a2ea551a07ad5f",
+        "us-west-2": "ami-0839681594a1d7627",
     },
     # Managed by BuildKite
     # from https://s3.amazonaws.com/buildkite-aws-stack/latest/aws-stack.yml
     "linux-amd64-cpu": {
-        "us-west-2": "ami-075d4c25d5f0c17c1",
+        "us-west-2": "ami-00f2127550cf03658",
     },
     "pipeline-loader": {
-        "us-west-2": "ami-075d4c25d5f0c17c1",
+        "us-west-2": "ami-00f2127550cf03658",
     },
     "linux-arm64-cpu": {
-        "us-west-2": "ami-0952c6fb6db9a9891",
+        "us-west-2": "ami-0c5789068f4a2d1b5",
     },
 }
 
diff --git a/tests/buildkite/infrastructure/common_blocks/utils.py b/tests/buildkite/infrastructure/common_blocks/utils.py
new file mode 100644
index 000000000000..27a0835e8dc0
--- /dev/null
+++ b/tests/buildkite/infrastructure/common_blocks/utils.py
@@ -0,0 +1,97 @@
+import re
+
+import boto3
+import botocore
+
+
+def stack_exists(args, *, stack_name):
+    client = boto3.client("cloudformation", region_name=args.aws_region)
+    waiter = client.get_waiter("stack_exists")
+    try:
+        waiter.wait(StackName=stack_name, WaiterConfig={"MaxAttempts": 1})
+        return True
+    except botocore.exceptions.WaiterError as e:
+        return False
+
+
+def create_or_update_stack(
+    args, *, client, stack_name, template_url=None, template_body=None, params=None
+):
+    kwargs = {
+        "StackName": stack_name,
+        "Capabilities": [
+            "CAPABILITY_IAM",
+            "CAPABILITY_NAMED_IAM",
+            "CAPABILITY_AUTO_EXPAND",
+        ],
+    }
+    if template_url:
+        kwargs["TemplateURL"] = template_url
+    if template_body:
+        kwargs["TemplateBody"] = template_body
+    if params:
+        kwargs["Parameters"] = params
+
+    if stack_exists(args, stack_name=stack_name):
+        print(f"Stack {stack_name} already exists. Updating...")
+        try:
+            response = client.update_stack(**kwargs)
+            return {"StackName": stack_name, "Action": "update"}
+        except botocore.exceptions.ClientError as e:
+            if e.response["Error"]["Code"] == "ValidationError" and re.search(
+                "No updates are to be performed", e.response["Error"]["Message"]
+            ):
+                print(f"No update was made to {stack_name}")
+                return {"StackName": stack_name, "Action": "noop"}
+            else:
+                raise e
+    else:
+        kwargs.update({"OnFailure": "ROLLBACK", "EnableTerminationProtection": False})
+        response = client.create_stack(**kwargs)
+        return {"StackName": stack_name, "Action": "create"}
+
+
+def replace_stack(
+    args, *, client, stack_name, template_url=None, template_body=None, params=None
+):
+    """Delete an existing stack and create a new stack with identical name"""
+
+    if not stack_exists(args, stack_name=stack_name):
+        raise ValueError(f"Stack {stack_name} does not exist")
+    r = client.delete_stack(StackName=stack_name)
+    delete_waiter = client.get_waiter("stack_delete_complete")
+    delete_waiter.wait(StackName=stack_name)
+
+    kwargs = {
+        "StackName": stack_name,
+        "Capabilities": [
+            "CAPABILITY_IAM",
+            "CAPABILITY_NAMED_IAM",
+            "CAPABILITY_AUTO_EXPAND",
+        ],
+        "OnFailure": "ROLLBACK",
+        "EnableTerminationProtection": False,
+    }
+    if template_url:
+        kwargs["TemplateURL"] = template_url
+    if template_body:
+        kwargs["TemplateBody"] = template_body
+    if params:
+        kwargs["Parameters"] = params
+    response = client.create_stack(**kwargs)
+    return {"StackName": stack_name, "Action": "create"}
+
+
+def wait(promise, *, client):
+    stack_name = promise["StackName"]
+    print(f"Waiting for {stack_name}...")
+    if promise["Action"] == "create":
+        waiter = client.get_waiter("stack_create_complete")
+        waiter.wait(StackName=stack_name)
+        print(f"Finished creating stack {stack_name}")
+    elif promise["Action"] == "update":
+        waiter = client.get_waiter("stack_update_complete")
+        waiter.wait(StackName=stack_name)
+        print(f"Finished updating stack {stack_name}")
+    elif promise["Action"] != "noop":
+        raise ValueError(f"Invalid promise {promise}")
diff --git a/tests/buildkite/infrastructure/worker-image-pipeline/create_worker_image_pipelines.py b/tests/buildkite/infrastructure/worker-image-pipeline/create_worker_image_pipelines.py
index 0c71d5e772f2..8051b991da51 100644
--- a/tests/buildkite/infrastructure/worker-image-pipeline/create_worker_image_pipelines.py
+++ b/tests/buildkite/infrastructure/worker-image-pipeline/create_worker_image_pipelines.py
@@ -2,6 +2,7 @@
 import copy
 import json
 import os
+import sys
 from urllib.request import urlopen
 
 import boto3
@@ -9,6 +10,9 @@
 from metadata import IMAGE_PARAMS
 
 current_dir = os.path.dirname(__file__)
+sys.path.append(os.path.join(current_dir, ".."))
+
+from common_blocks.utils import replace_stack, wait
 
 BUILDKITE_CF_TEMPLATE_URL = (
     "https://s3.amazonaws.com/buildkite-aws-stack/latest/aws-stack.yml"
@@ -47,6 +51,9 @@ def main(args):
 
     ami_mapping = get_ami_mapping()
 
+    client = boto3.client("cloudformation", region_name=args.aws_region)
+    promises = []
+
     for stack_id in IMAGE_PARAMS:
         stack_id_full = get_full_stack_id(stack_id)
         print(f"Creating EC2 image builder stack {stack_id_full}...")
@@ -55,28 +62,20 @@ def main(args):
             stack_id=stack_id, aws_region=args.aws_region, ami_mapping=ami_mapping
         )
 
-        client = boto3.client("cloudformation", region_name=args.aws_region)
-        response = client.create_stack(
-            StackName=stack_id_full,
-            TemplateBody=ec2_image_pipeline_template,
-            Capabilities=[
-                "CAPABILITY_IAM",
-                "CAPABILITY_NAMED_IAM",
-                "CAPABILITY_AUTO_EXPAND",
-            ],
-            OnFailure="ROLLBACK",
-            EnableTerminationProtection=False,
-            Parameters=params,
+        promise = replace_stack(
+            args,
+            client=client,
+            stack_name=stack_id_full,
+            template_body=ec2_image_pipeline_template,
+            params=params,
         )
+        promises.append(promise)
         print(
             f"EC2 image builder stack {stack_id_full} is in progress in the background"
         )
 
-    for stack_id in IMAGE_PARAMS:
-        stack_id_full = get_full_stack_id(stack_id)
-        waiter = client.get_waiter("stack_create_complete")
-        waiter.wait(StackName=stack_id_full)
-        print(f"EC2 image builder stack {stack_id_full} is now finished.")
+    for promise in promises:
+        wait(promise, client=client)
 
 
 if __name__ == "__main__":
diff --git a/tests/buildkite/infrastructure/worker-image-pipeline/ec2-image-builder-pipeline-template.yml b/tests/buildkite/infrastructure/worker-image-pipeline/ec2-image-builder-pipeline-template.yml
index 478adf3d4dab..8d3bafa72f08 100644
--- a/tests/buildkite/infrastructure/worker-image-pipeline/ec2-image-builder-pipeline-template.yml
+++ b/tests/buildkite/infrastructure/worker-image-pipeline/ec2-image-builder-pipeline-template.yml
@@ -58,7 +58,7 @@ Resources:
   BootstrapComponent:
     Type: AWS::ImageBuilder::Component
     Properties:
-      Name: !Sub "${AWS::StackName}-bootstrap-component"
+      Name: !Join ["-", [!Ref AWS::StackName, "bootstrap-component", !Select [2, !Split ['/', !Ref AWS::StackId]]]]
       Platform: !Ref InstanceOperatingSystem
       Version: "1.0.0"
       Description: Execute a bootstrap script.
@@ -67,7 +67,7 @@ Resources:
   Recipe:
     Type: AWS::ImageBuilder::ImageRecipe
     Properties:
-      Name: !Sub "${AWS::StackName}-image"
+      Name: !Join ["-", [!Ref AWS::StackName, "image", !Select [2, !Split ['/', !Ref AWS::StackId]]]]
       Components:
         - ComponentArn: !Ref BootstrapComponent
       ParentImage: !Ref BaseImageId
@@ -83,7 +83,7 @@ Resources:
   Infrastructure:
     Type: AWS::ImageBuilder::InfrastructureConfiguration
     Properties:
-      Name: !Sub "${AWS::StackName}-image-pipeline-infrastructure"
+      Name: !Join ["-", [!Ref AWS::StackName, "image-pipeline-infrastructure", !Select [2, !Split ['/', !Ref AWS::StackId]]]]
       InstanceProfileName: !Ref InstanceProfile
       InstanceTypes:
         - !Ref InstanceType
@@ -93,7 +93,7 @@ Resources:
   Distribution:
     Type: AWS::ImageBuilder::DistributionConfiguration
     Properties:
-      Name: !Sub "${AWS::StackName}-image-pipeline-distribution-config"
+      Name: !Join ["-", [!Ref AWS::StackName, "image-pipeline-distribution-config", !Select [2, !Split ['/', !Ref AWS::StackId]]]]
       Distributions:
         - Region: !Ref AWS::Region
           AmiDistributionConfiguration: {}
@@ -102,7 +102,7 @@ Resources:
   Pipeline:
     Type: AWS::ImageBuilder::ImagePipeline
     Properties:
-      Name: !Sub "${AWS::StackName}-image-pipeline"
+      Name: !Join ["-", [!Ref AWS::StackName, "image-pipeline", !Select [2, !Split ['/', !Ref AWS::StackId]]]]
       DistributionConfigurationArn: !Ref Distribution
       ImageRecipeArn: !Ref Recipe
       InfrastructureConfigurationArn: !Ref Infrastructure
diff --git a/tests/buildkite/infrastructure/worker-image-pipeline/metadata.py b/tests/buildkite/infrastructure/worker-image-pipeline/metadata.py
index c74914e54840..37100209fe2e 100644
--- a/tests/buildkite/infrastructure/worker-image-pipeline/metadata.py
+++ b/tests/buildkite/infrastructure/worker-image-pipeline/metadata.py
@@ -13,6 +13,6 @@
         "BootstrapScript": "windows-gpu-bootstrap.yml",
         "InstanceType": "g4dn.2xlarge",
         "InstanceOperatingSystem": "Windows",
-        "VolumeSize": "80",  # in GiBs
+        "VolumeSize": "120",  # in GiBs
     },
 }
diff --git a/tests/buildkite/infrastructure/worker-image-pipeline/windows-gpu-bootstrap.yml b/tests/buildkite/infrastructure/worker-image-pipeline/windows-gpu-bootstrap.yml
index ef3fade44f16..03fb105a7011 100644
--- a/tests/buildkite/infrastructure/worker-image-pipeline/windows-gpu-bootstrap.yml
+++ b/tests/buildkite/infrastructure/worker-image-pipeline/windows-gpu-bootstrap.yml
@@ -15,9 +15,9 @@ phases:
               choco --version
               choco feature enable -n=allowGlobalConfirmation
 
-              # CMake 3.18
-              Write-Host '>>> Installing CMake 3.18...'
-              choco install cmake --version 3.18.0 --installargs "ADD_CMAKE_TO_PATH=System"
+              # CMake 3.25
+              Write-Host '>>> Installing CMake 3.25...'
+              choco install cmake --version 3.25.2 --installargs "ADD_CMAKE_TO_PATH=System"
               if ($LASTEXITCODE -ne 0) { throw "Last command failed" }
 
               # Notepad++
@@ -45,18 +45,18 @@ phases:
               choco install graphviz
               if ($LASTEXITCODE -ne 0) { throw "Last command failed" }
 
-              # Install Visual Studio Community 2017 (15.9)
-              Write-Host '>>> Installing Visual Studio 2017 Community (15.9)...'
-              choco install visualstudio2017community --version 15.9.23.0 `
+              # Install Visual Studio 2022 Community
+              Write-Host '>>> Installing Visual Studio 2022 Community...'
+              choco install visualstudio2022community `
                   --params "--wait --passive --norestart"
               if ($LASTEXITCODE -ne 0) { throw "Last command failed" }
-              choco install visualstudio2017-workload-nativedesktop --params `
+              choco install visualstudio2022-workload-nativedesktop --params `
                   "--wait --passive --norestart --includeOptional"
               if ($LASTEXITCODE -ne 0) { throw "Last command failed" }
 
-              # Install CUDA 11.0
-              Write-Host '>>> Installing CUDA 11.0...'
-              choco install cuda --version 11.0.3
+              # Install CUDA 11.8
+              Write-Host '>>> Installing CUDA 11.8...'
+              choco install cuda --version=11.8.0.52206
               if ($LASTEXITCODE -ne 0) { throw "Last command failed" }
 
               # Install Python packages
diff --git a/tests/buildkite/pipeline.yml b/tests/buildkite/pipeline.yml
index e2a4fcaf2405..2f01c36dbc04 100644
--- a/tests/buildkite/pipeline.yml
+++ b/tests/buildkite/pipeline.yml
@@ -22,11 +22,11 @@ steps:
       queue: linux-amd64-cpu
   - wait
   #### -------- BUILD --------
-  - label: ":console: Run clang-tidy"
-    command: "tests/buildkite/run-clang-tidy.sh"
-    key: run-clang-tidy
-    agents:
-      queue: linux-amd64-cpu
+  # - label: ":console: Run clang-tidy"
+  #   command: "tests/buildkite/run-clang-tidy.sh"
+  #   key: run-clang-tidy
+  #  agents:
+  #    queue: linux-amd64-cpu
   - wait
   - label: ":console: Build CPU"
     command: "tests/buildkite/build-cpu.sh"
diff --git a/tests/buildkite/test-cpp-gpu.sh b/tests/buildkite/test-cpp-gpu.sh
index d1192c763c41..75a600d7a855 100755
--- a/tests/buildkite/test-cpp-gpu.sh
+++ b/tests/buildkite/test-cpp-gpu.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 
 source tests/buildkite/conftest.sh
 
-echo "--- Run Google Tests with CUDA, using 4 GPUs"
+echo "--- Run Google Tests with CUDA, using a GPU"
 buildkite-agent artifact download "build/testxgboost" . --step build-cuda
 chmod +x build/testxgboost
 tests/ci_build/ci_build.sh gpu nvidia-docker \
@@ -12,11 +12,13 @@ tests/ci_build/ci_build.sh gpu nvidia-docker \
   --build-arg RAPIDS_VERSION_ARG=$RAPIDS_VERSION \
   build/testxgboost
 
-echo "--- Run Google Tests with CUDA, using 4 GPUs, RMM enabled"
-rm -rfv build/
-buildkite-agent artifact download "build/testxgboost" . --step build-cuda-with-rmm
-chmod +x build/testxgboost
-tests/ci_build/ci_build.sh rmm nvidia-docker \
-  --build-arg CUDA_VERSION_ARG=$CUDA_VERSION \
-  --build-arg RAPIDS_VERSION_ARG=$RAPIDS_VERSION bash -c \
-  "source activate gpu_test && build/testxgboost --use-rmm-pool"
+# Disabled until https://github.com/dmlc/xgboost/issues/8619 is resolved
+# echo "--- Run Google Tests with CUDA, using a GPU, RMM enabled"
+# rm -rfv build/
+# buildkite-agent artifact download "build/testxgboost" . --step build-cuda-with-rmm
+# chmod +x build/testxgboost
+# tests/ci_build/ci_build.sh rmm nvidia-docker \
+#   --build-arg CUDA_VERSION_ARG=$CUDA_VERSION \
+#   --build-arg RAPIDS_VERSION_ARG=$RAPIDS_VERSION bash -c \
+#   --build-arg NCCL_VERSION_ARG=$NCCL_VERSION bash -c \
+#   "source activate gpu_test && build/testxgboost --use-rmm-pool"
diff --git a/tests/ci_build/Dockerfile.clang_tidy b/tests/ci_build/Dockerfile.clang_tidy
index b0166f240b8b..3a33a080cd8b 100644
--- a/tests/ci_build/Dockerfile.clang_tidy
+++ b/tests/ci_build/Dockerfile.clang_tidy
@@ -15,8 +15,8 @@ RUN \
     add-apt-repository -u 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-11 main' && \
     apt-get update && \
     apt-get install -y llvm-11 clang-tidy-11 clang-11 && \
-    wget -nv -nc https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh --no-check-certificate && \
-    bash cmake-3.14.0-Linux-x86_64.sh --skip-license --prefix=/usr
+    wget -nv -nc https://cmake.org/files/v3.18/cmake-3.18.0-Linux-x86_64.sh --no-check-certificate && \
+    bash cmake-3.18.0-Linux-x86_64.sh --skip-license --prefix=/usr
 
 # Set default clang-tidy version
 RUN \
diff --git a/tests/ci_build/Dockerfile.cpu b/tests/ci_build/Dockerfile.cpu
index 54c3c3af4ec7..4e56d2bf5c98 100644
--- a/tests/ci_build/Dockerfile.cpu
+++ b/tests/ci_build/Dockerfile.cpu
@@ -12,8 +12,8 @@ RUN \
     apt-get update && \
     apt-get install -y tar unzip wget git build-essential doxygen graphviz llvm libasan2 libidn11 ninja-build gcc-8 g++-8 openjdk-8-jdk-headless && \
     # CMake
-    wget -nv -nc https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh --no-check-certificate && \
-    bash cmake-3.14.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
+    wget -nv -nc https://cmake.org/files/v3.18/cmake-3.18.0-Linux-x86_64.sh --no-check-certificate && \
+    bash cmake-3.18.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
     # Python
     wget -nv https://github.com/conda-forge/miniforge/releases/latest/download/Mambaforge-Linux-x86_64.sh && \
     bash Mambaforge-Linux-x86_64.sh -b -p /opt/python
diff --git a/tests/ci_build/Dockerfile.gpu b/tests/ci_build/Dockerfile.gpu
index d149638acc92..48830722d33c 100644
--- a/tests/ci_build/Dockerfile.gpu
+++ b/tests/ci_build/Dockerfile.gpu
@@ -22,10 +22,10 @@ ENV PATH=/opt/python/bin:$PATH
 RUN \
     conda install -c conda-forge mamba && \
     mamba create -n gpu_test -c rapidsai-nightly -c rapidsai -c nvidia -c conda-forge -c defaults \
-        python=3.9 cudf=$RAPIDS_VERSION_ARG* rmm=$RAPIDS_VERSION_ARG* cudatoolkit=$CUDA_VERSION_ARG \
+        python=3.10 cudf=$RAPIDS_VERSION_ARG* rmm=$RAPIDS_VERSION_ARG* cudatoolkit=$CUDA_VERSION_ARG \
         dask dask-cuda=$RAPIDS_VERSION_ARG* dask-cudf=$RAPIDS_VERSION_ARG* cupy \
         numpy pytest pytest-timeout scipy scikit-learn pandas matplotlib wheel python-kubernetes urllib3 graphviz hypothesis \
-        pyspark cloudpickle cuda-python=11.7.0 && \
+        pyspark cloudpickle cuda-python && \
     mamba clean --all && \
     conda run --no-capture-output -n gpu_test pip install buildkite-test-collector
 
diff --git a/tests/ci_build/Dockerfile.gpu_build_centos7 b/tests/ci_build/Dockerfile.gpu_build_centos7
index 4168e430d91e..bfe967d02312 100644
--- a/tests/ci_build/Dockerfile.gpu_build_centos7
+++ b/tests/ci_build/Dockerfile.gpu_build_centos7
@@ -1,6 +1,7 @@
 ARG CUDA_VERSION_ARG
 FROM nvidia/cuda:$CUDA_VERSION_ARG-devel-centos7
 ARG CUDA_VERSION_ARG
+ARG NCCL_VERSION_ARG
 
 # Install all basic requirements
 RUN \
@@ -21,7 +22,7 @@ RUN \
 # NCCL2 (License: https://docs.nvidia.com/deeplearning/sdk/nccl-sla/index.html)
 RUN \
     export CUDA_SHORT=`echo $CUDA_VERSION_ARG | grep -o -E '[0-9]+\.[0-9]'` && \
-    export NCCL_VERSION=2.13.4-1 && \
+    export NCCL_VERSION=$NCCL_VERSION_ARG && \
     wget -nv -nc https://developer.download.nvidia.com/compute/machine-learning/repos/rhel7/x86_64/nvidia-machine-learning-repo-rhel7-1.0.0-1.x86_64.rpm && \
     rpm -i nvidia-machine-learning-repo-rhel7-1.0.0-1.x86_64.rpm && \
     yum -y update && \
diff --git a/tests/ci_build/Dockerfile.gpu_build_r_centos7 b/tests/ci_build/Dockerfile.gpu_build_r_centos7
index 54a63a242202..675e50af3a44 100644
--- a/tests/ci_build/Dockerfile.gpu_build_r_centos7
+++ b/tests/ci_build/Dockerfile.gpu_build_r_centos7
@@ -36,8 +36,8 @@ RUN \
     bash Miniconda3.sh -b -p /opt/python && \
     /opt/python/bin/python -m pip install auditwheel awscli && \
     # CMake
-    wget -nv -nc https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh --no-check-certificate && \
-    bash cmake-3.14.0-Linux-x86_64.sh --skip-license --prefix=/usr
+    wget -nv -nc https://cmake.org/files/v3.18/cmake-3.18.0-Linux-x86_64.sh --no-check-certificate && \
+    bash cmake-3.18.0-Linux-x86_64.sh --skip-license --prefix=/usr
 
 ENV GOSU_VERSION 1.10
 
diff --git a/tests/ci_build/Dockerfile.jvm b/tests/ci_build/Dockerfile.jvm
index 9c7001adebf4..0b2c29597f8b 100644
--- a/tests/ci_build/Dockerfile.jvm
+++ b/tests/ci_build/Dockerfile.jvm
@@ -12,8 +12,8 @@ RUN \
     wget -nv -nc -O Miniconda3.sh https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh && \
     bash Miniconda3.sh -b -p /opt/python && \
     # CMake
-    wget -nv -nc https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh --no-check-certificate && \
-    bash cmake-3.14.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
+    wget -nv -nc https://cmake.org/files/v3.18/cmake-3.18.0-Linux-x86_64.sh --no-check-certificate && \
+    bash cmake-3.18.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
     # Maven
     wget -nv -nc https://archive.apache.org/dist/maven/maven-3/3.6.1/binaries/apache-maven-3.6.1-bin.tar.gz && \
     tar xvf apache-maven-3.6.1-bin.tar.gz -C /opt && \
diff --git a/tests/ci_build/Dockerfile.jvm_gpu_build b/tests/ci_build/Dockerfile.jvm_gpu_build
index cddbb1f65729..f214052ae061 100644
--- a/tests/ci_build/Dockerfile.jvm_gpu_build
+++ b/tests/ci_build/Dockerfile.jvm_gpu_build
@@ -1,6 +1,7 @@
 ARG CUDA_VERSION_ARG
 FROM nvidia/cuda:$CUDA_VERSION_ARG-devel-centos7
 ARG CUDA_VERSION_ARG
+ARG NCCL_VERSION_ARG
 
 # Install all basic requirements
 RUN \
@@ -14,8 +15,8 @@ RUN \
     wget -nv -nc -O Miniconda3.sh https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh && \
     bash Miniconda3.sh -b -p /opt/python && \
     # CMake
-    wget -nv -nc https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh --no-check-certificate && \
-    bash cmake-3.14.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
+    wget -nv -nc https://cmake.org/files/v3.18/cmake-3.18.0-Linux-x86_64.sh --no-check-certificate && \
+    bash cmake-3.18.0-Linux-x86_64.sh --skip-license --prefix=/usr && \
     # Maven
     wget -nv -nc https://archive.apache.org/dist/maven/maven-3/3.6.1/binaries/apache-maven-3.6.1-bin.tar.gz && \
     tar xvf apache-maven-3.6.1-bin.tar.gz -C /opt && \
@@ -24,7 +25,7 @@ RUN \
 # NCCL2 (License: https://docs.nvidia.com/deeplearning/sdk/nccl-sla/index.html)
 RUN \
     export CUDA_SHORT=`echo $CUDA_VERSION_ARG | grep -o -E '[0-9]+\.[0-9]'` && \
-    export NCCL_VERSION=2.13.4-1 && \
+    export NCCL_VERSION=$NCCL_VERSION_ARG && \
     yum-config-manager --add-repo http://developer.download.nvidia.com/compute/cuda/repos/rhel7/x86_64/cuda-rhel7.repo && \
     yum -y update && \
     yum install -y libnccl-${NCCL_VERSION}+cuda${CUDA_SHORT} libnccl-devel-${NCCL_VERSION}+cuda${CUDA_SHORT} libnccl-static-${NCCL_VERSION}+cuda${CUDA_SHORT}
diff --git a/tests/ci_build/Dockerfile.rmm b/tests/ci_build/Dockerfile.rmm
index 0fbe44865456..0d3dfeca93b2 100644
--- a/tests/ci_build/Dockerfile.rmm
+++ b/tests/ci_build/Dockerfile.rmm
@@ -1,7 +1,8 @@
 ARG CUDA_VERSION_ARG
-FROM nvidia/cuda:$CUDA_VERSION_ARG-devel-ubuntu18.04
+FROM nvidia/cuda:$CUDA_VERSION_ARG-devel-ubuntu20.04
 ARG CUDA_VERSION_ARG
 ARG RAPIDS_VERSION_ARG
+ARG NCCL_VERSION_ARG
 
 # Environment
 ENV DEBIAN_FRONTEND noninteractive
@@ -19,7 +20,7 @@ RUN \
 # NCCL2 (License: https://docs.nvidia.com/deeplearning/sdk/nccl-sla/index.html)
 RUN \
     export CUDA_SHORT=`echo $CUDA_VERSION_ARG | grep -o -E '[0-9]+\.[0-9]'` && \
-    export NCCL_VERSION=2.13.4-1 && \
+    export NCCL_VERSION=$NCCL_VERSION_ARG && \
     apt-get update && \
     apt-get install -y --allow-downgrades --allow-change-held-packages libnccl2=${NCCL_VERSION}+cuda${CUDA_SHORT} libnccl-dev=${NCCL_VERSION}+cuda${CUDA_SHORT}
 
@@ -29,7 +30,7 @@ ENV PATH=/opt/python/bin:$PATH
 RUN \
     conda install -c conda-forge mamba && \
     mamba create -n gpu_test -c rapidsai-nightly -c rapidsai -c nvidia -c conda-forge -c defaults \
-        python=3.9 rmm=$RAPIDS_VERSION_ARG* cudatoolkit=$CUDA_VERSION_ARG cmake && \
+        python=3.10 rmm=$RAPIDS_VERSION_ARG* cudatoolkit=$CUDA_VERSION_ARG cmake && \
     mamba clean --all
 
 ENV GOSU_VERSION 1.10
diff --git a/tests/ci_build/build_r_pkg_with_cuda_win64.sh b/tests/ci_build/build_r_pkg_with_cuda_win64.sh
index f83795775b2c..042ac2329ad8 100644
--- a/tests/ci_build/build_r_pkg_with_cuda_win64.sh
+++ b/tests/ci_build/build_r_pkg_with_cuda_win64.sh
@@ -15,7 +15,7 @@ mv xgboost/ xgboost_rpack/
 
 mkdir build
 cd build
-cmake .. -G"Visual Studio 15 2017 Win64" -DUSE_CUDA=ON -DR_LIB=ON -DLIBR_HOME="c:\\Program Files\\R\\R-3.6.3"
+cmake .. -G"Visual Studio 17 2022" -A x64 -DUSE_CUDA=ON -DR_LIB=ON -DLIBR_HOME="c:\\Program Files\\R\\R-3.6.3"
 cmake --build . --config Release --parallel
 cd ..
 
diff --git a/tests/ci_build/conda_env/cpp_test.yml b/tests/ci_build/conda_env/cpp_test.yml
new file mode 100644
index 000000000000..80ce65cc1cea
--- /dev/null
+++ b/tests/ci_build/conda_env/cpp_test.yml
@@ -0,0 +1,11 @@
+# conda environment for CPP test on Linux distributions
+name: cpp_test
+channels:
+- defaults
+- conda-forge
+dependencies:
+- cmake
+- ninja
+- c-compiler
+- cxx-compiler
+- gtest
diff --git a/tests/ci_build/conda_env/cpu_test.yml b/tests/ci_build/conda_env/cpu_test.yml
index 98c7a5928892..4d74c5832e97 100644
--- a/tests/ci_build/conda_env/cpu_test.yml
+++ b/tests/ci_build/conda_env/cpu_test.yml
@@ -36,7 +36,8 @@ dependencies:
 - cloudpickle
 - shap
 - modin
+# TODO: Replace it with pyspark>=3.4 once 3.4 released.
+# - https://ml-team-public-read.s3.us-west-2.amazonaws.com/pyspark-3.4.0.dev0.tar.gz
+- pyspark>=3.3.1
 - pip:
   - datatable
-  # TODO: Replace it with pyspark>=3.4 once 3.4 released.
-  - https://ml-team-public-read.s3.us-west-2.amazonaws.com/pyspark-3.4.0.dev0.tar.gz
diff --git a/tests/ci_build/conda_env/sdist_test.yml b/tests/ci_build/conda_env/sdist_test.yml
new file mode 100644
index 000000000000..fc1e710973b2
--- /dev/null
+++ b/tests/ci_build/conda_env/sdist_test.yml
@@ -0,0 +1,13 @@
+# conda environment for source distribution test.
+name: sdist_test
+channels:
+- defaults
+- conda-forge
+dependencies:
+- python=3.8
+- pip
+- wheel
+- cmake
+- ninja
+- c-compiler
+- cxx-compiler
diff --git a/tests/ci_build/insert_vcomp140.py b/tests/ci_build/insert_vcomp140.py
index e45c7d204b73..cfa8d792dee2 100644
--- a/tests/ci_build/insert_vcomp140.py
+++ b/tests/ci_build/insert_vcomp140.py
@@ -1,19 +1,102 @@
-import sys
-import re
-import zipfile
+import argparse
+import base64
 import glob
+import hashlib
+import os
+import pathlib
+import re
+import shutil
+import tempfile
+
+VCOMP140_PATH = "C:\\Windows\\System32\\vcomp140.dll"
+
+
+def get_sha256sum(path):
+    return (
+        base64.urlsafe_b64encode(hashlib.sha256(open(path, "rb").read()).digest())
+        .decode("latin1")
+        .rstrip("=")
+    )
+
+
+def update_record(*, wheel_content_dir, xgboost_version):
+    vcomp140_size = os.path.getsize(VCOMP140_PATH)
+    vcomp140_hash = get_sha256sum(VCOMP140_PATH)
+
+    record_path = wheel_content_dir / pathlib.Path(
+        f"xgboost-{xgboost_version}.dist-info/RECORD"
+    )
+    with open(record_path, "r") as f:
+        record_content = f.read()
+    record_content += f"xgboost-{xgboost_version}.data/data/xgboost/vcomp140.dll,"
+    record_content += f"sha256={vcomp140_hash},{vcomp140_size}\n"
+    with open(record_path, "w") as f:
+        f.write(record_content)
+
+
+def main(args):
+    candidates = list(sorted(glob.glob(args.wheel_path)))
+    for wheel_path in candidates:
+        print(f"Processing wheel {wheel_path}")
+        m = re.search(r"xgboost-(.*)\+.*-py3", wheel_path)
+        if not m:
+            raise ValueError(f"Wheel {wheel_path} has unexpected name")
+        version = m.group(1)
+        print(f"  Detected version for {wheel_path}: {version}")
+        print(f"  Inserting vcomp140.dll into {wheel_path}...")
+        with tempfile.TemporaryDirectory() as tempdir:
+            wheel_content_dir = pathlib.Path(tempdir) / "wheel_content"
+            print(f"    Extract {wheel_path} into {wheel_content_dir}")
+            shutil.unpack_archive(
+                wheel_path, extract_dir=wheel_content_dir, format="zip"
+            )
+            data_dir = wheel_content_dir / pathlib.Path(
+                f"xgboost-{version}.data/data/xgboost"
+            )
+            data_dir.mkdir(parents=True, exist_ok=True)
+
+            print(f"    Copy {VCOMP140_PATH} -> {data_dir}")
+            shutil.copy(VCOMP140_PATH, data_dir)
+
+            print(f"    Update RECORD")
+            update_record(wheel_content_dir=wheel_content_dir, xgboost_version=version)
+
+            print(f"    Content of {wheel_content_dir}:")
+            for e in sorted(wheel_content_dir.rglob("*")):
+                if e.is_file():
+                    r = e.relative_to(wheel_content_dir)
+                    print(f"      {r}")
+
+            print(f"    Create new wheel...")
+            new_wheel_tmp_path = pathlib.Path(tempdir) / "new_wheel"
+            shutil.make_archive(
+                str(new_wheel_tmp_path.resolve()),
+                format="zip",
+                root_dir=wheel_content_dir,
+            )
+            new_wheel_tmp_path = new_wheel_tmp_path.resolve().with_suffix(".zip")
+            new_wheel_tmp_path = new_wheel_tmp_path.rename(
+                new_wheel_tmp_path.with_suffix(".whl")
+            )
+            print(f"    Created new wheel {new_wheel_tmp_path}")
+
+            # Rename the old wheel with suffix .bak
+            # The new wheel takes the name of the old wheel
+            wheel_path_obj = pathlib.Path(wheel_path).resolve()
+            backup_path = wheel_path_obj.with_suffix(".whl.bak")
+            print(f"    Rename {wheel_path_obj} -> {backup_path}")
+            wheel_path_obj.replace(backup_path)
+            print(f"    Rename {new_wheel_tmp_path} -> {wheel_path_obj}")
+            new_wheel_tmp_path.replace(wheel_path_obj)
 
-if len(sys.argv) != 2:
-    print('Usage: {} [wheel]'.format(sys.argv[0]))
-    sys.exit(1)
+            shutil.rmtree(wheel_content_dir)
 
-vcomp140_path = 'C:\\Windows\\System32\\vcomp140.dll'
 
-for wheel_path in sorted(glob.glob(sys.argv[1])):
-    m = re.search(r'xgboost-(.*)-py3', wheel_path)
-    assert m, f'wheel_path = {wheel_path}'
-    version = m.group(1)
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "wheel_path", type=str, help="Path to wheel (wildcard permitted)"
+    )
+    args = parser.parse_args()
 
-    print(f"Inserting vcomp140.dll into {wheel_path}...")
-    with zipfile.ZipFile(wheel_path, 'a') as f:
-        f.write(vcomp140_path, 'xgboost-{}.data/data/xgboost/vcomp140.dll'.format(version))
+    main(args)
diff --git a/tests/cpp/common/test_categorical.cc b/tests/cpp/common/test_categorical.cc
index cc8eb0f7e6c4..4e6e696ecfdd 100644
--- a/tests/cpp/common/test_categorical.cc
+++ b/tests/cpp/common/test_categorical.cc
@@ -1,11 +1,14 @@
 /*!
- * Copyright 2021 by XGBoost Contributors
+ * Copyright 2021-2022 by XGBoost Contributors
  */
 #include <gtest/gtest.h>
+#include <xgboost/json.h>
+#include <xgboost/learner.h>
 
 #include <limits>
 
 #include "../../../src/common/categorical.h"
+#include "../helpers.h"
 
 namespace xgboost {
 namespace common {
@@ -15,29 +18,76 @@ TEST(Categorical, Decision) {
 
   ASSERT_TRUE(common::InvalidCat(a));
   std::vector<uint32_t> cats(256, 0);
-  ASSERT_TRUE(Decision(cats, a, true));
+  ASSERT_TRUE(Decision(cats, a));
 
   // larger than size
   a = 256;
-  ASSERT_TRUE(Decision(cats, a, true));
+  ASSERT_TRUE(Decision(cats, a));
 
   // negative
   a = -1;
-  ASSERT_TRUE(Decision(cats, a, true));
+  ASSERT_TRUE(Decision(cats, a));
 
   CatBitField bits{cats};
   bits.Set(0);
   a = -0.5;
-  ASSERT_TRUE(Decision(cats, a, true));
+  ASSERT_TRUE(Decision(cats, a));
 
   // round toward 0
   a = 0.5;
-  ASSERT_FALSE(Decision(cats, a, true));
+  ASSERT_FALSE(Decision(cats, a));
 
   // valid
   a = 13;
   bits.Set(a);
-  ASSERT_FALSE(Decision(bits.Bits(), a, true));
+  ASSERT_FALSE(Decision(bits.Bits(), a));
+}
+
+/**
+ * Test for running inference with input category greater than the one stored in tree.
+ */
+TEST(Categorical, MinimalSet) {
+  std::size_t constexpr kRows = 256, kCols = 1, kCat = 3;
+  std::vector<FeatureType> types{FeatureType::kCategorical};
+  auto Xy =
+      RandomDataGenerator{kRows, kCols, 0.0}.Type(types).MaxCategory(kCat).GenerateDMatrix(true);
+
+  std::unique_ptr<Learner> learner{Learner::Create({Xy})};
+  learner->SetParam("max_depth", "1");
+  learner->SetParam("tree_method", "hist");
+  learner->Configure();
+  learner->UpdateOneIter(0, Xy);
+
+  Json model{Object{}};
+  learner->SaveModel(&model);
+  auto tree = model["learner"]["gradient_booster"]["model"]["trees"][0];
+  ASSERT_GE(get<I32Array const>(tree["categories"]).size(), 1);
+  auto v = get<I32Array const>(tree["categories"])[0];
+
+  HostDeviceVector<float> predt;
+  {
+    std::vector<float> data{static_cast<float>(kCat),
+                            static_cast<float>(kCat + 1), 32.0f, 33.0f, 34.0f};
+    auto test = GetDMatrixFromData(data, data.size(), kCols);
+    learner->Predict(test, false, &predt, 0, 0, false, /*pred_leaf=*/true);
+    ASSERT_EQ(predt.Size(), data.size());
+    auto const& h_predt = predt.ConstHostSpan();
+    for (auto v : h_predt) {
+      ASSERT_EQ(v, 1);  // left child of root node
+    }
+  }
+
+  {
+    std::unique_ptr<Learner> learner{Learner::Create({Xy})};
+    learner->LoadModel(model);
+    std::vector<float> data = {static_cast<float>(v)};
+    auto test = GetDMatrixFromData(data, data.size(), kCols);
+    learner->Predict(test, false, &predt, 0, 0, false, /*pred_leaf=*/true);
+    auto const& h_predt = predt.ConstHostSpan();
+    for (auto v : h_predt) {
+      ASSERT_EQ(v, 2);  // right child of root node
+    }
+  }
 }
 }  // namespace common
 }  // namespace xgboost
diff --git a/tests/cpp/data/test_array_interface.cc b/tests/cpp/data/test_array_interface.cc
index 3c2e0e38d5c3..9bf7010dc797 100644
--- a/tests/cpp/data/test_array_interface.cc
+++ b/tests/cpp/data/test_array_interface.cc
@@ -1,10 +1,12 @@
-/*!
- * Copyright 2020-2021 by XGBoost Contributors
+/**
+ * Copyright 2020-2023 by XGBoost Contributors
  */
 #include <gtest/gtest.h>
 #include <xgboost/host_device_vector.h>
 #include "../helpers.h"
 #include "../../../src/data/array_interface.h"
+#include "dmlc/logging.h"
+#include "xgboost/json.h"
 
 namespace xgboost {
 TEST(ArrayInterface, Initialize) {
@@ -33,9 +35,8 @@ TEST(ArrayInterface, Error) {
   Json column { Object() };
   std::vector<Json> j_shape {Json(Integer(static_cast<Integer::Int>(kRows)))};
   column["shape"] = Array(j_shape);
-  std::vector<Json> j_data {
-    Json(Integer(reinterpret_cast<Integer::Int>(nullptr))),
-        Json(Boolean(false))};
+  std::vector<Json> j_data{Json(Integer(reinterpret_cast<Integer::Int>(nullptr))),
+                           Json(Boolean(false))};
 
   auto const& column_obj = get<Object>(column);
   std::string typestr{"<f4"};
@@ -45,6 +46,10 @@ TEST(ArrayInterface, Error) {
   EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n), dmlc::Error);
   column["version"] = 3;
   // missing data
+  EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n),
+               dmlc::Error);
+  // null data
+  column["data"] = Null{};
   EXPECT_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n),
                dmlc::Error);
   column["data"] = j_data;
@@ -63,6 +68,19 @@ TEST(ArrayInterface, Error) {
       Json(Boolean(false))};
   column["data"] = j_data;
   EXPECT_NO_THROW(ArrayInterfaceHandler::ExtractData(column_obj, n));
+  // null data in mask
+  column["mask"] = Object{};
+  column["mask"]["data"] = Null{};
+  common::Span<RBitField8::value_type> s_mask;
+  EXPECT_THROW(ArrayInterfaceHandler::ExtractMask(column_obj, &s_mask), dmlc::Error);
+
+  get<Object>(column).erase("mask");
+  // misaligned.
+  j_data = {Json(Integer(reinterpret_cast<Integer::Int>(
+                reinterpret_cast<char const*>(storage.ConstHostPointer()) + 1))),
+            Json(Boolean(false))};
+  column["data"] = j_data;
+  EXPECT_THROW({ ArrayInterface<1> arr{column}; }, dmlc::Error);
 }
 
 TEST(ArrayInterface, GetElement) {
diff --git a/tests/cpp/data/test_gradient_index.cc b/tests/cpp/data/test_gradient_index.cc
index 6233f1b25231..66e9cfe0c525 100644
--- a/tests/cpp/data/test_gradient_index.cc
+++ b/tests/cpp/data/test_gradient_index.cc
@@ -68,6 +68,30 @@ TEST(GradientIndex, FromCategoricalBasic) {
   }
 }
 
+TEST(GradientIndex, FromCategoricalLarge) {
+  size_t constexpr kRows = 1000, kCats = 512, kCols = 1;
+  bst_bin_t max_bins = 8;
+  auto x = GenerateRandomCategoricalSingleColumn(kRows, kCats);
+  auto m = GetDMatrixFromData(x, kRows, 1);
+  Context ctx;
+
+  auto &h_ft = m->Info().feature_types.HostVector();
+  h_ft.resize(kCols, FeatureType::kCategorical);
+
+  BatchParam p{max_bins, 0.8};
+  {
+    GHistIndexMatrix gidx(m.get(), max_bins, p.sparse_thresh, false, Context{}.Threads(), {});
+    ASSERT_TRUE(gidx.index.GetBinTypeSize() == common::kUint16BinsTypeSize);
+  }
+  {
+    for (auto const &page : m->GetBatches<GHistIndexMatrix>(p)) {
+      common::HistogramCuts cut = page.cut;
+      GHistIndexMatrix gidx{m->Info(), std::move(cut), max_bins};
+      ASSERT_EQ(gidx.MaxNumBinPerFeat(), kCats);
+    }
+  }
+}
+
 TEST(GradientIndex, PushBatch) {
   size_t constexpr kRows = 64, kCols = 4;
   bst_bin_t max_bins = 64;
diff --git a/tests/cpp/data/test_simple_dmatrix.cc b/tests/cpp/data/test_simple_dmatrix.cc
index 266115731fd6..198663872fc3 100644
--- a/tests/cpp/data/test_simple_dmatrix.cc
+++ b/tests/cpp/data/test_simple_dmatrix.cc
@@ -1,13 +1,19 @@
-// Copyright by Contributors
+/**
+ * Copyright 2016-2023 by XGBoost Contributors
+ */
 #include <xgboost/data.h>
 
-#include <array>
+#include <array>   // std::array
+#include <limits>  // std::numeric_limits
+#include <memory>  // std::unique_ptr
 
-#include "../../../src/data/adapter.h"
-#include "../../../src/data/simple_dmatrix.h"
-#include "../filesystem.h"  // dmlc::TemporaryDirectory
-#include "../helpers.h"
+#include "../../../src/data/adapter.h"         // ArrayAdapter
+#include "../../../src/data/simple_dmatrix.h"  // SimpleDMatrix
+#include "../filesystem.h"                     // dmlc::TemporaryDirectory
+#include "../helpers.h"                        // RandomDataGenerator,CreateSimpleTestData
 #include "xgboost/base.h"
+#include "xgboost/host_device_vector.h"  // HostDeviceVector
+#include "xgboost/string_view.h"         // StringView
 
 using namespace xgboost;  // NOLINT
 
@@ -298,6 +304,17 @@ TEST(SimpleDMatrix, Slice) {
   ASSERT_EQ(out->Info().num_col_, out->Info().num_col_);
   ASSERT_EQ(out->Info().num_row_, ridxs.size());
   ASSERT_EQ(out->Info().num_nonzero_, ridxs.size() * kCols);  // dense
+
+  {
+    HostDeviceVector<float> data;
+    auto arr_str = RandomDataGenerator{kRows, kCols, 0.0}.GenerateArrayInterface(&data);
+    auto adapter = data::ArrayAdapter{StringView{arr_str}};
+    auto n_threads = 2;
+    std::unique_ptr<DMatrix> p_fmat{
+        DMatrix::Create(&adapter, std::numeric_limits<float>::quiet_NaN(), n_threads, "")};
+    std::unique_ptr<DMatrix> slice{p_fmat->Slice(ridxs)};
+    ASSERT_LE(slice->Ctx()->Threads(), n_threads);
+  }
 }
 
 TEST(SimpleDMatrix, SaveLoadBinary) {
diff --git a/tests/cpp/tree/test_node_partition.cc b/tests/cpp/tree/test_node_partition.cc
new file mode 100644
index 000000000000..883c8e68ffa6
--- /dev/null
+++ b/tests/cpp/tree/test_node_partition.cc
@@ -0,0 +1,24 @@
+/**
+ * Copyright 2023 by XGBoost contributors
+ */
+#include <gtest/gtest.h>
+#include <xgboost/task.h>
+#include <xgboost/tree_updater.h>
+
+namespace xgboost {
+TEST(Updater, HasNodePosition) {
+  Context ctx;
+  ObjInfo task{ObjInfo::kRegression, true, true};
+  std::unique_ptr<TreeUpdater> up{TreeUpdater::Create("grow_histmaker", &ctx, task)};
+  ASSERT_TRUE(up->HasNodePosition());
+
+  up.reset(TreeUpdater::Create("grow_quantile_histmaker", &ctx, task));
+  ASSERT_TRUE(up->HasNodePosition());
+
+#if defined(XGBOOST_USE_CUDA)
+  ctx.gpu_id = 0;
+  up.reset(TreeUpdater::Create("grow_gpu_hist", &ctx, task));
+  ASSERT_TRUE(up->HasNodePosition());
+#endif  // defined(XGBOOST_USE_CUDA)
+}
+}  // namespace xgboost
diff --git a/tests/python-gpu/test_device_quantile_dmatrix.py b/tests/python-gpu/test_device_quantile_dmatrix.py
index 2c3a7a760a59..b3d7ef660fd4 100644
--- a/tests/python-gpu/test_device_quantile_dmatrix.py
+++ b/tests/python-gpu/test_device_quantile_dmatrix.py
@@ -139,3 +139,17 @@ def test_to_csr(self, n_samples, n_features, sparsity) -> None:
             booster.predict(xgb.DMatrix(d_m.get_data())),
             atol=1e-6,
         )
+
+    def test_ltr(self) -> None:
+        import cupy as cp
+        X, y, qid, w = tm.make_ltr(100, 3, 3, 5)
+        # make sure GPU is used to run sketching.
+        cpX = cp.array(X)
+        Xy_qdm = xgb.QuantileDMatrix(cpX, y, qid=qid, weight=w)
+        Xy = xgb.DMatrix(X, y, qid=qid, weight=w)
+        xgb.train({"tree_method": "gpu_hist", "objective": "rank:ndcg"}, Xy)
+
+        from_dm = xgb.QuantileDMatrix(X, weight=w, ref=Xy)
+        from_qdm = xgb.QuantileDMatrix(X, weight=w, ref=Xy_qdm)
+
+        assert tm.predictor_equal(from_qdm, from_dm)
diff --git a/tests/python-gpu/test_gpu_interaction_constraints.py b/tests/python-gpu/test_gpu_interaction_constraints.py
index 885cf5bf9901..434cc15dacd5 100644
--- a/tests/python-gpu/test_gpu_interaction_constraints.py
+++ b/tests/python-gpu/test_gpu_interaction_constraints.py
@@ -1,8 +1,14 @@
-import numpy as np
 import sys
+
+import numpy as np
+import pandas as pd
+
+import xgboost as xgb
+
 sys.path.append("tests/python")
 # Don't import the test class, otherwise they will run twice.
 import test_interaction_constraints as test_ic  # noqa
+
 rng = np.random.RandomState(1994)
 
 
@@ -10,7 +16,34 @@ class TestGPUInteractionConstraints:
     cputest = test_ic.TestInteractionConstraints()
 
     def test_interaction_constraints(self):
-        self.cputest.run_interaction_constraints(tree_method='gpu_hist')
+        self.cputest.run_interaction_constraints(tree_method="gpu_hist")
 
     def test_training_accuracy(self):
-        self.cputest.training_accuracy(tree_method='gpu_hist')
+        self.cputest.training_accuracy(tree_method="gpu_hist")
+
+    # case where different number of features can occur in the evaluator
+    def test_issue_8730(self):
+        X = pd.DataFrame(
+            zip(range(0, 100), range(200, 300), range(300, 400), range(400, 500)),
+            columns=["A", "B", "C", "D"],
+        )
+        y = np.array([*([0] * 50), *([1] * 50)])
+        dm = xgb.DMatrix(X, label=y)
+
+        params = {
+            "eta": 0.16095019509249486,
+            "min_child_weight": 1,
+            "subsample": 0.688567929338029,
+            "colsample_bynode": 0.7,
+            "gamma": 5.666579817418348e-06,
+            "lambda": 0.14943712232059794,
+            "grow_policy": "depthwise",
+            "max_depth": 3,
+            "tree_method": "gpu_hist",
+            "interaction_constraints": [["A", "B"], ["B", "D", "C"], ["C", "D"]],
+            "objective": "count:poisson",
+            "eval_metric": "poisson-nloglik",
+            "verbosity": 0,
+        }
+
+        xgb.train(params, dm, num_boost_round=100)
diff --git a/tests/python-gpu/test_gpu_prediction.py b/tests/python-gpu/test_gpu_prediction.py
index 3dedb0637e7c..6bd33d0d640f 100644
--- a/tests/python-gpu/test_gpu_prediction.py
+++ b/tests/python-gpu/test_gpu_prediction.py
@@ -216,6 +216,7 @@ def predict_dense(x):
     def test_inplace_predict_cupy(self):
         self.run_inplace_predict_cupy(0)
 
+    @pytest.mark.xfail
     @pytest.mark.skipif(**tm.no_cupy())
     @pytest.mark.mgpu
     def test_inplace_predict_cupy_specified_device(self):
@@ -338,13 +339,21 @@ def run_predict_leaf_booster(self, param, num_rounds, dataset):
     @given(predict_parameter_strategy, tm.dataset_strategy)
     @settings(deadline=None, max_examples=20, print_blob=True)
     def test_predict_leaf_gbtree(self, param, dataset):
+        # Unsupported for random forest
+        if param.get("num_parallel_tree", 1) > 1 and dataset.name.endswith("-l1"):
+            return
+
         param['booster'] = 'gbtree'
         param['tree_method'] = 'gpu_hist'
         self.run_predict_leaf_booster(param, 10, dataset)
 
     @given(predict_parameter_strategy, tm.dataset_strategy)
     @settings(deadline=None, max_examples=20, print_blob=True)
-    def test_predict_leaf_dart(self, param, dataset):
+    def test_predict_leaf_dart(self, param: dict, dataset: tm.TestDataset) -> None:
+        # Unsupported for random forest
+        if param.get("num_parallel_tree", 1) > 1 and dataset.name.endswith("-l1"):
+            return
+
         param['booster'] = 'dart'
         param['tree_method'] = 'gpu_hist'
         self.run_predict_leaf_booster(param, 10, dataset)
diff --git a/tests/python-gpu/test_gpu_updaters.py b/tests/python-gpu/test_gpu_updaters.py
index e86152327711..10610d1a8255 100644
--- a/tests/python-gpu/test_gpu_updaters.py
+++ b/tests/python-gpu/test_gpu_updaters.py
@@ -215,3 +215,34 @@ def test_specified_gpu_id_gpu_update(self, dataset, gpu_id):
     @pytest.mark.parametrize("weighted", [True, False])
     def test_adaptive(self, weighted) -> None:
         self.cputest.run_adaptive("gpu_hist", weighted)
+
+    @pytest.mark.skipif(**tm.no_pandas())
+    def test_issue8824(self):
+        # column sampling by node crashes because shared pointers go out of scope
+        import pandas as pd
+
+        data = pd.DataFrame(np.random.rand(1024, 8))
+        data.columns = "x" + data.columns.astype(str)
+        features = data.columns
+        data["y"] = data.sum(axis=1) < 4
+        dtrain = xgb.DMatrix(data[features], label=data["y"])
+        model = xgb.train(
+            dtrain=dtrain,
+            params={
+                "max_depth": 5,
+                "learning_rate": 0.05,
+                "objective": "binary:logistic",
+                "tree_method": "gpu_hist",
+                "colsample_bytree": 0.5,
+                "colsample_bylevel": 0.5,
+                "colsample_bynode": 0.5,  # Causes issues
+                "reg_alpha": 0.05,
+                "reg_lambda": 0.005,
+                "seed": 66,
+                "subsample": 0.5,
+                "gamma": 0.2,
+                "predictor": "auto",
+                "eval_metric": "auc",
+            },
+            num_boost_round=150,
+        )
diff --git a/tests/python/test_collective.py b/tests/python/test_collective.py
index f7de0400d21f..32b0a67a76e3 100644
--- a/tests/python/test_collective.py
+++ b/tests/python/test_collective.py
@@ -39,6 +39,37 @@ def test_rabit_communicator():
         assert worker.exitcode == 0
 
 
+# TODO(rongou): remove this once we remove the rabit api.
+def run_rabit_api_worker(rabit_env, world_size):
+    with xgb.rabit.RabitContext(rabit_env):
+        assert xgb.rabit.get_world_size() == world_size
+        assert xgb.rabit.is_distributed()
+        assert xgb.rabit.get_processor_name().decode() == socket.gethostname()
+        ret = xgb.rabit.broadcast('test1234', 0)
+        assert str(ret) == 'test1234'
+        ret = xgb.rabit.allreduce(np.asarray([1, 2, 3]), xgb.rabit.Op.SUM)
+        assert np.array_equal(ret, np.asarray([2, 4, 6]))
+
+
+# TODO(rongou): remove this once we remove the rabit api.
+def test_rabit_api():
+    world_size = 2
+    tracker = RabitTracker(host_ip='127.0.0.1', n_workers=world_size)
+    tracker.start(world_size)
+    rabit_env = []
+    for k, v in tracker.worker_envs().items():
+        rabit_env.append(f"{k}={v}".encode())
+    workers = []
+    for _ in range(world_size):
+        worker = multiprocessing.Process(target=run_rabit_api_worker,
+                                         args=(rabit_env, world_size))
+        workers.append(worker)
+        worker.start()
+    for worker in workers:
+        worker.join()
+        assert worker.exitcode == 0
+
+
 def run_federated_worker(port, world_size, rank):
     with xgb.collective.CommunicatorContext(xgboost_communicator='federated',
                                             federated_server_address=f'localhost:{port}',
diff --git a/tests/python/test_dmatrix.py b/tests/python/test_dmatrix.py
index b7933eac4c53..5c9232895fed 100644
--- a/tests/python/test_dmatrix.py
+++ b/tests/python/test_dmatrix.py
@@ -326,7 +326,7 @@ def test_sparse_dmatrix_csr(self):
         nrow = 100
         ncol = 1000
         x = rand(nrow, ncol, density=0.0005, format='csr', random_state=rng)
-        assert x.indices.max() < ncol - 1
+        assert x.indices.max() < ncol
         x.data[:] = 1
         dtrain = xgb.DMatrix(x, label=rng.binomial(1, 0.3, nrow))
         assert (dtrain.num_row(), dtrain.num_col()) == (nrow, ncol)
diff --git a/tests/python/test_quantile_dmatrix.py b/tests/python/test_quantile_dmatrix.py
index 65ccfa4e5e76..9000d99881d4 100644
--- a/tests/python/test_quantile_dmatrix.py
+++ b/tests/python/test_quantile_dmatrix.py
@@ -9,7 +9,9 @@
     make_batches,
     make_batches_sparse,
     make_categorical,
+    make_ltr,
     make_sparse_regression,
+    predictor_equal,
 )
 
 import xgboost as xgb
@@ -218,6 +220,16 @@ def test_predict(self) -> None:
         b = booster.predict(qXy)
         np.testing.assert_allclose(a, b)
 
+    def test_ltr(self) -> None:
+        X, y, qid, w = make_ltr(100, 3, 3, 5)
+        Xy_qdm = xgb.QuantileDMatrix(X, y, qid=qid, weight=w)
+        Xy = xgb.DMatrix(X, y, qid=qid, weight=w)
+        xgb.train({"tree_method": "hist", "objective": "rank:ndcg"}, Xy)
+
+        from_qdm = xgb.QuantileDMatrix(X, weight=w, ref=Xy_qdm)
+        from_dm = xgb.QuantileDMatrix(X, weight=w, ref=Xy)
+        assert predictor_equal(from_qdm, from_dm)
+
     # we don't test empty Quantile DMatrix in single node construction.
     @given(
         strategies.integers(1, 1000),
diff --git a/tests/python/test_spark/test_spark_local.py b/tests/python/test_spark/test_spark_local.py
index 03981d955040..574e96388737 100644
--- a/tests/python/test_spark/test_spark_local.py
+++ b/tests/python/test_spark/test_spark_local.py
@@ -41,6 +41,16 @@
 pytestmark = testing.timeout(60)
 
 
+def no_sparse_unwrap():
+    try:
+        from pyspark.sql.functions import unwrap_udt
+
+    except ImportError:
+        return {"reason": "PySpark<3.4", "condition": True}
+
+    return {"reason": "PySpark<3.4", "condition": False}
+
+
 class XgboostLocalTest(SparkTestCase):
     def setUp(self):
         logging.getLogger().setLevel("INFO")
@@ -390,28 +400,6 @@ def setUp(self):
                 "expected_prediction_with_base_margin",
             ],
         )
-        self.ranker_df_train = self.session.createDataFrame(
-            [
-                (Vectors.dense(1.0, 2.0, 3.0), 0, 0),
-                (Vectors.dense(4.0, 5.0, 6.0), 1, 0),
-                (Vectors.dense(9.0, 4.0, 8.0), 2, 0),
-                (Vectors.sparse(3, {1: 1.0, 2: 5.5}), 0, 1),
-                (Vectors.sparse(3, {1: 6.0, 2: 7.5}), 1, 1),
-                (Vectors.sparse(3, {1: 8.0, 2: 9.5}), 2, 1),
-            ],
-            ["features", "label", "qid"],
-        )
-        self.ranker_df_test = self.session.createDataFrame(
-            [
-                (Vectors.dense(1.5, 2.0, 3.0), 0, -1.87988),
-                (Vectors.dense(4.5, 5.0, 6.0), 0, 0.29556),
-                (Vectors.dense(9.0, 4.5, 8.0), 0, 2.36570),
-                (Vectors.sparse(3, {1: 1.0, 2: 6.0}), 1, -1.87988),
-                (Vectors.sparse(3, {1: 6.0, 2: 7.0}), 1, -0.30612),
-                (Vectors.sparse(3, {1: 8.0, 2: 10.5}), 1, 2.44826),
-            ],
-            ["features", "qid", "expected_prediction"],
-        )
 
         self.reg_df_sparse_train = self.session.createDataFrame(
             [
@@ -1007,6 +995,7 @@ def test_classifier_with_feature_names_types_weights(self):
         model = classifier.fit(self.cls_df_train)
         model.transform(self.cls_df_test).collect()
 
+    @pytest.mark.skipif(**no_sparse_unwrap())
     def test_regressor_with_sparse_optim(self):
         regressor = SparkXGBRegressor(missing=0.0)
         model = regressor.fit(self.reg_df_sparse_train)
@@ -1023,6 +1012,7 @@ def test_regressor_with_sparse_optim(self):
         for row1, row2 in zip(pred_result, pred_result2):
             self.assertTrue(np.isclose(row1.prediction, row2.prediction, atol=1e-3))
 
+    @pytest.mark.skipif(**no_sparse_unwrap())
     def test_classifier_with_sparse_optim(self):
         cls = SparkXGBClassifier(missing=0.0)
         model = cls.fit(self.cls_df_sparse_train)
@@ -1039,15 +1029,6 @@ def test_classifier_with_sparse_optim(self):
         for row1, row2 in zip(pred_result, pred_result2):
             self.assertTrue(np.allclose(row1.probability, row2.probability, rtol=1e-3))
 
-    def test_ranker(self):
-        ranker = SparkXGBRanker(qid_col="qid")
-        assert ranker.getOrDefault(ranker.objective) == "rank:pairwise"
-        model = ranker.fit(self.ranker_df_train)
-        pred_result = model.transform(self.ranker_df_test).collect()
-
-        for row in pred_result:
-            assert np.isclose(row.prediction, row.expected_prediction, rtol=1e-3)
-
     def test_empty_validation_data(self) -> None:
         for tree_method in [
             "hist",
@@ -1130,3 +1111,63 @@ def test_early_stop_param_validation(self):
     def test_unsupported_params(self):
         with pytest.raises(ValueError, match="evals_result"):
             SparkXGBClassifier(evals_result={})
+
+
+class XgboostRankerLocalTest(SparkTestCase):
+    def setUp(self):
+        self.session.conf.set("spark.sql.execution.arrow.maxRecordsPerBatch", "8")
+        self.ranker_df_train = self.session.createDataFrame(
+            [
+                (Vectors.dense(1.0, 2.0, 3.0), 0, 0),
+                (Vectors.dense(4.0, 5.0, 6.0), 1, 0),
+                (Vectors.dense(9.0, 4.0, 8.0), 2, 0),
+                (Vectors.sparse(3, {1: 1.0, 2: 5.5}), 0, 1),
+                (Vectors.sparse(3, {1: 6.0, 2: 7.5}), 1, 1),
+                (Vectors.sparse(3, {1: 8.0, 2: 9.5}), 2, 1),
+            ],
+            ["features", "label", "qid"],
+        )
+        self.ranker_df_test = self.session.createDataFrame(
+            [
+                (Vectors.dense(1.5, 2.0, 3.0), 0, -1.87988),
+                (Vectors.dense(4.5, 5.0, 6.0), 0, 0.29556),
+                (Vectors.dense(9.0, 4.5, 8.0), 0, 2.36570),
+                (Vectors.sparse(3, {1: 1.0, 2: 6.0}), 1, -1.87988),
+                (Vectors.sparse(3, {1: 6.0, 2: 7.0}), 1, -0.30612),
+                (Vectors.sparse(3, {1: 8.0, 2: 10.5}), 1, 2.44826),
+            ],
+            ["features", "qid", "expected_prediction"],
+        )
+        self.ranker_df_train_1 = self.session.createDataFrame(
+            [
+                (Vectors.sparse(3, {1: 1.0, 2: 5.5}), 0, 9),
+                (Vectors.sparse(3, {1: 6.0, 2: 7.5}), 1, 9),
+                (Vectors.sparse(3, {1: 8.0, 2: 9.5}), 2, 9),
+                (Vectors.dense(1.0, 2.0, 3.0), 0, 8),
+                (Vectors.dense(4.0, 5.0, 6.0), 1, 8),
+                (Vectors.dense(9.0, 4.0, 8.0), 2, 8),
+                (Vectors.sparse(3, {1: 1.0, 2: 5.5}), 0, 7),
+                (Vectors.sparse(3, {1: 6.0, 2: 7.5}), 1, 7),
+                (Vectors.sparse(3, {1: 8.0, 2: 9.5}), 2, 7),
+                (Vectors.dense(1.0, 2.0, 3.0), 0, 6),
+                (Vectors.dense(4.0, 5.0, 6.0), 1, 6),
+                (Vectors.dense(9.0, 4.0, 8.0), 2, 6),
+            ]
+            * 4,
+            ["features", "label", "qid"],
+        )
+
+    def test_ranker(self):
+        ranker = SparkXGBRanker(qid_col="qid")
+        assert ranker.getOrDefault(ranker.objective) == "rank:pairwise"
+        model = ranker.fit(self.ranker_df_train)
+        pred_result = model.transform(self.ranker_df_test).collect()
+
+        for row in pred_result:
+            assert np.isclose(row.prediction, row.expected_prediction, rtol=1e-3)
+
+    def test_ranker_qid_sorted(self):
+        ranker = SparkXGBRanker(qid_col="qid", num_workers=4)
+        assert ranker.getOrDefault(ranker.objective) == "rank:pairwise"
+        model = ranker.fit(self.ranker_df_train_1)
+        model.transform(self.ranker_df_test).collect()
diff --git a/tests/python/test_updaters.py b/tests/python/test_updaters.py
index e28f173860e7..cd159df67dcb 100644
--- a/tests/python/test_updaters.py
+++ b/tests/python/test_updaters.py
@@ -458,6 +458,22 @@ def get_score(config: Dict) -> float:
         config_0 = json.loads(booster_0.save_config())
         np.testing.assert_allclose(get_score(config_0), get_score(config_1) + 1)
 
+        evals_result: Dict[str, Dict[str, list]] = {}
+        xgb.train(
+            {
+                "tree_method": tree_method,
+                "objective": "reg:absoluteerror",
+                "subsample": 0.8
+            },
+            Xy,
+            num_boost_round=10,
+            evals=[(Xy, "Train")],
+            evals_result=evals_result,
+        )
+        mae = evals_result["Train"]["mae"]
+        assert mae[-1] < 20.0
+        assert tm.non_increasing(mae)
+
     @pytest.mark.skipif(**tm.no_sklearn())
     @pytest.mark.parametrize(
         "tree_method,weighted", [
diff --git a/tests/python/test_with_pandas.py b/tests/python/test_with_pandas.py
index e4289c1cdcef..84352d15143e 100644
--- a/tests/python/test_with_pandas.py
+++ b/tests/python/test_with_pandas.py
@@ -112,7 +112,6 @@ def test_pandas(self):
 
         # test Index as columns
         df = pd.DataFrame([[1, 1.1], [2, 2.2]], columns=pd.Index([1, 2]))
-        print(df.columns, isinstance(df.columns, pd.Index))
         Xy = xgb.DMatrix(df)
         np.testing.assert_equal(np.array(Xy.feature_names), np.array(["1", "2"]))
 
diff --git a/tests/python/test_with_shap.py b/tests/python/test_with_shap.py
index 1e03e070035c..080dda3c3ed0 100644
--- a/tests/python/test_with_shap.py
+++ b/tests/python/test_with_shap.py
@@ -4,7 +4,7 @@
 
 try:
     import shap
-except ImportError:
+except Exception:
     shap = None
     pass
 
diff --git a/tests/python/test_with_sklearn.py b/tests/python/test_with_sklearn.py
index 17114d2dde39..62b3fe6b56a6 100644
--- a/tests/python/test_with_sklearn.py
+++ b/tests/python/test_with_sklearn.py
@@ -2,6 +2,7 @@
 import importlib.util
 import json
 import os
+import pickle
 import random
 import tempfile
 from typing import Callable, Optional
@@ -636,26 +637,74 @@ def test_sklearn_n_jobs():
 
 def test_parameters_access():
     from sklearn import datasets
-    params = {'updater': 'grow_gpu_hist', 'subsample': .5, 'n_jobs': -1}
+
+    params = {"updater": "grow_gpu_hist", "subsample": 0.5, "n_jobs": -1}
     clf = xgb.XGBClassifier(n_estimators=1000, **params)
-    assert clf.get_params()['updater'] == 'grow_gpu_hist'
-    assert clf.get_params()['subsample'] == .5
-    assert clf.get_params()['n_estimators'] == 1000
+    assert clf.get_params()["updater"] == "grow_gpu_hist"
+    assert clf.get_params()["subsample"] == 0.5
+    assert clf.get_params()["n_estimators"] == 1000
 
     clf = xgb.XGBClassifier(n_estimators=1, nthread=4)
     X, y = datasets.load_iris(return_X_y=True)
     clf.fit(X, y)
 
     config = json.loads(clf.get_booster().save_config())
-    assert int(config['learner']['generic_param']['nthread']) == 4
+    assert int(config["learner"]["generic_param"]["nthread"]) == 4
 
     clf.set_params(nthread=16)
     config = json.loads(clf.get_booster().save_config())
-    assert int(config['learner']['generic_param']['nthread']) == 16
+    assert int(config["learner"]["generic_param"]["nthread"]) == 16
 
     clf.predict(X)
     config = json.loads(clf.get_booster().save_config())
-    assert int(config['learner']['generic_param']['nthread']) == 16
+    assert int(config["learner"]["generic_param"]["nthread"]) == 16
+
+    clf = xgb.XGBClassifier(n_estimators=2)
+    assert clf.tree_method is None
+    assert clf.get_params()["tree_method"] is None
+    clf.fit(X, y)
+    assert clf.get_params()["tree_method"] is None
+
+    def save_load(clf: xgb.XGBClassifier) -> xgb.XGBClassifier:
+        with tempfile.TemporaryDirectory() as tmpdir:
+            path = os.path.join(tmpdir, "model.json")
+            clf.save_model(path)
+            clf = xgb.XGBClassifier()
+            clf.load_model(path)
+        return clf
+
+    def get_tm(clf: xgb.XGBClassifier) -> str:
+        tm = json.loads(clf.get_booster().save_config())["learner"]["gradient_booster"][
+            "gbtree_train_param"
+        ]["tree_method"]
+        return tm
+
+    assert get_tm(clf) == "exact"
+
+    clf = pickle.loads(pickle.dumps(clf))
+
+    assert clf.tree_method is None
+    assert clf.n_estimators == 2
+    assert clf.get_params()["tree_method"] is None
+    assert clf.get_params()["n_estimators"] == 2
+    assert get_tm(clf) == "exact"  # preserved for pickle
+
+    clf = save_load(clf)
+
+    assert clf.tree_method is None
+    assert clf.n_estimators == 2
+    assert clf.get_params()["tree_method"] is None
+    assert clf.get_params()["n_estimators"] == 2
+    assert get_tm(clf) == "auto"  # discarded for save/load_model
+
+    clf.set_params(tree_method="hist")
+    assert clf.get_params()["tree_method"] == "hist"
+    clf = pickle.loads(pickle.dumps(clf))
+    assert clf.get_params()["tree_method"] == "hist"
+    clf = save_load(clf)
+    # FIXME(jiamingy): We should remove this behavior once we remove parameters
+    # serialization for skl save/load_model.
+    assert clf.get_params()["tree_method"] == "hist"
 
 
 def test_kwargs_error():
@@ -695,13 +744,19 @@ def test_sklearn_clone():
 
 def test_sklearn_get_default_params():
     from sklearn.datasets import load_digits
+
     digits_2class = load_digits(n_class=2)
-    X = digits_2class['data']
-    y = digits_2class['target']
+    X = digits_2class["data"]
+    y = digits_2class["target"]
     cls = xgb.XGBClassifier()
-    assert cls.get_params()['base_score'] is None
+    assert cls.get_params()["base_score"] is None
     cls.fit(X[:4, ...], y[:4, ...])
-    assert cls.get_params()['base_score'] is not None
+    base_score = float(
+        json.loads(cls.get_booster().save_config())["learner"]["learner_model_param"][
+            "base_score"
+        ]
+    )
+    np.testing.assert_equal(base_score, 0.5)
 
 
 def run_validation_weights(model):
@@ -1029,9 +1084,9 @@ def test_pandas_input():
 
     clf_isotonic = CalibratedClassifierCV(model, cv="prefit", method="isotonic")
     clf_isotonic.fit(train, target)
-    assert isinstance(
-        clf_isotonic.calibrated_classifiers_[0].base_estimator, xgb.XGBClassifier
-    )
+    clf = clf_isotonic.calibrated_classifiers_[0]
+    est = clf.estimator if hasattr(clf, "estimator") else clf.base_estimator
+    assert isinstance(est, xgb.XGBClassifier)
     np.testing.assert_allclose(np.array(clf_isotonic.classes_), np.array([0, 1]))
 
 
diff --git a/tests/python/testing.py b/tests/python/testing.py
index 63d33de97e5a..f0f09911f078 100644
--- a/tests/python/testing.py
+++ b/tests/python/testing.py
@@ -466,7 +466,22 @@ def make_categorical(
     return df, label
 
 
-def _cat_sampled_from():
+def make_ltr(
+    n_samples: int, n_features: int, n_query_groups: int, max_rel: int
+) -> Tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
+    """Make a dataset for testing LTR."""
+    rng = np.random.default_rng(1994)
+    X = rng.normal(0, 1.0, size=n_samples * n_features).reshape(n_samples, n_features)
+    y = rng.integers(0, max_rel, size=n_samples)
+    qid = rng.integers(0, n_query_groups, size=n_samples)
+    w = rng.normal(0, 1.0, size=n_query_groups)
+    w -= np.min(w)
+    w /= np.max(w)
+    qid = np.sort(qid)
+    return X, y, qid, w
+
+
+def _cat_sampled_from() -> strategies.SearchStrategy:
     @strategies.composite
     def _make_cat(draw):
         n_samples = draw(strategies.integers(2, 512))
@@ -775,6 +790,19 @@ def __exit__(self, *args):
                 os.remove(f)
 
 
+def predictor_equal(lhs: xgb.DMatrix, rhs: xgb.DMatrix) -> bool:
+    """Assert whether two DMatrices contain the same predictors."""
+    lcsr = lhs.get_data()
+    rcsr = rhs.get_data()
+    return all(
+        (
+            np.array_equal(lcsr.data, rcsr.data),
+            np.array_equal(lcsr.indices, rcsr.indices),
+            np.array_equal(lcsr.indptr, rcsr.indptr),
+        )
+    )
+
+
 @contextmanager
 def captured_output():
     """Reassign stdout temporarily in order to test printed statements