diff --git a/.gitignore b/.gitignore
index d09973a9..87c614f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,11 +27,12 @@
 *.out
 *.app
 
-# custom files and directories 
+# custom files and directories
 third_party/_submodules
 _out/
 build/
 bin/
+obj/
 .idea
 node_modules
 
@@ -41,4 +42,4 @@ cmd/protoc-gen-cpp-tableau-loader/protoc-gen-cpp-tableau-loader
 cmd/protoc-gen-go-tableau-loader/protoc-gen-go-tableau-loader
 
 test/go-tableau-loader/go-tableau-loader
-_lab/ts/src/protoconf
\ No newline at end of file
+_lab/ts/src/protoconf
diff --git a/cmd/protoc-gen-cpp-tableau-loader/embed/load.pc.cc b/cmd/protoc-gen-cpp-tableau-loader/embed/load.pc.cc
index 5c60d98b..52a44b99 100644
--- a/cmd/protoc-gen-cpp-tableau-loader/embed/load.pc.cc
+++ b/cmd/protoc-gen-cpp-tableau-loader/embed/load.pc.cc
@@ -1,5 +1,9 @@
 #include "load.pc.h"
 
+#if __cplusplus >= 201703L
+#include <filesystem>
+#endif
+
 #include "logger.pc.h"
 #include "util.pc.h"
 
@@ -175,8 +179,13 @@ bool LoadMessageWithPatch(google::protobuf::Message& msg, const std::string& pat
     // patch path specified in PatchPaths, then use it instead of PatchDirs.
     patch_paths = iter->second;
   } else {
+    std::string filename = name + util::Format2Ext(fmt);
     for (auto&& patch_dir : options->patch_dirs) {
-      patch_paths.emplace_back(patch_dir + name + util::Format2Ext(fmt));
+#if __cplusplus >= 201703L
+      patch_paths.emplace_back((std::filesystem::path(patch_dir) / filename).make_preferred().string());
+#else
+      patch_paths.emplace_back(patch_dir + kPathSeperator + filename);
+#endif
     }
   }
 
@@ -276,7 +285,12 @@ bool LoadMessage(google::protobuf::Message& msg, const std::string& dir, Format
     }
   }
   if (path.empty()) {
-    path = dir + name + util::Format2Ext(fmt);
+    std::string filename = name + util::Format2Ext(fmt);
+#if __cplusplus >= 201703L
+    path = (std::filesystem::path(dir) / filename).make_preferred().string();
+#else
+    path = dir + kPathSeperator + filename;
+#endif
   }
 
   const google::protobuf::Descriptor* descriptor = msg.GetDescriptor();
diff --git a/cmd/protoc-gen-cpp-tableau-loader/embed/messager.pc.h b/cmd/protoc-gen-cpp-tableau-loader/embed/messager.pc.h
index a021f59e..3949b256 100644
--- a/cmd/protoc-gen-cpp-tableau-loader/embed/messager.pc.h
+++ b/cmd/protoc-gen-cpp-tableau-loader/embed/messager.pc.h
@@ -1,6 +1,7 @@
 #pragma once
 #include <google/protobuf/message.h>
 
+#include <chrono>
 #include <functional>
 #include <string>
 
@@ -14,9 +15,6 @@ class Messager {
  public:
   struct Stats {
     std::chrono::microseconds duration;  // total load time consuming.
-    // TODO: crc32 of config file to decide whether changed or not
-    // std::string crc32;
-    // int64_t last_modified_time = 0; // unix timestamp
   };
 
  public:
diff --git a/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.cc b/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.cc
index 72cbc824..e6ec6c69 100644
--- a/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.cc
+++ b/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.cc
@@ -9,7 +9,6 @@
 
 #if __cplusplus >= 201703L
 #include <filesystem>
-namespace fs = std::filesystem;
 #else
 #ifdef _WIN32
 #include <direct.h>
@@ -26,9 +25,6 @@ namespace fs = std::filesystem;
 namespace tableau {
 #ifdef _WIN32
 #define mkdir(path, mode) _mkdir(path)
-static constexpr char kPathSeperator = '\\';
-#else
-static constexpr char kPathSeperator = '/';
 #endif
 
 static thread_local std::string g_err_msg;
@@ -44,7 +40,7 @@ namespace util {
 int Mkdir(const std::string& path) {
 #if __cplusplus >= 201703L
   std::error_code ec;
-  if (!fs::create_directories(path, ec)) {
+  if (!std::filesystem::create_directories(path, ec)) {
     if (ec) {
       std::cerr << "system error: " << ec.message() << std::endl;
       return -1;
@@ -72,7 +68,7 @@ int Mkdir(const std::string& path) {
 
 std::string GetDir(const std::string& path) {
 #if __cplusplus >= 201703L
-  return fs::path(path).parent_path().string();
+  return std::filesystem::path(path).parent_path().string();
 #else
   size_t pos = path.find_last_of(kPathSeperator);
   if (pos != std::string::npos) {
@@ -84,7 +80,7 @@ std::string GetDir(const std::string& path) {
 
 bool ExistsFile(const std::string& filename) {
 #if __cplusplus >= 201703L
-  return fs::exists(filename);
+  return std::filesystem::exists(filename);
 #else
   std::ifstream file(filename);
   // returns true if the file exists and is accessible
@@ -137,14 +133,6 @@ const std::string& Format2Ext(Format fmt) {
   }
 }
 
-bool Message2JSON(const google::protobuf::Message& msg, std::string& json) {
-  google::protobuf::util::JsonPrintOptions options;
-  options.add_whitespace = true;
-  options.always_print_primitive_fields = true;
-  options.preserve_proto_field_names = true;
-  return google::protobuf::util::MessageToJsonString(msg, &json, options).ok();
-}
-
 bool JSON2Message(const std::string& json, google::protobuf::Message& msg, const LoadOptions* options /* = nullptr */) {
   google::protobuf::util::Status status;
   if (options != nullptr) {
diff --git a/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.h b/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.h
index ab8d9e08..7e21f23b 100644
--- a/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.h
+++ b/cmd/protoc-gen-cpp-tableau-loader/embed/util.pc.h
@@ -11,6 +11,15 @@ namespace tableau {
 const std::string& GetErrMsg();
 void SetErrMsg(const std::string& msg);
 
+#if __cplusplus < 201703L
+// Platform-specific path separator
+#ifdef _WIN32
+constexpr char kPathSeperator = '\\';
+#else
+constexpr char kPathSeperator = '/';
+#endif
+#endif
+
 enum class Format {
   kUnknown,
   kJSON,
@@ -73,7 +82,6 @@ Format Ext2Format(const std::string& ext);
 // and the error message can be obtained by GetErrMsg().
 const std::string& Format2Ext(Format fmt);
 
-bool Message2JSON(const google::protobuf::Message& msg, std::string& json);
 bool JSON2Message(const std::string& json, google::protobuf::Message& msg, const LoadOptions* options = nullptr);
 bool Text2Message(const std::string& text, google::protobuf::Message& msg);
 bool Bin2Message(const std::string& bin, google::protobuf::Message& msg);
diff --git a/cmd/protoc-gen-cpp-tableau-loader/hub.go b/cmd/protoc-gen-cpp-tableau-loader/hub.go
index a181f686..c74fe51f 100644
--- a/cmd/protoc-gen-cpp-tableau-loader/hub.go
+++ b/cmd/protoc-gen-cpp-tableau-loader/hub.go
@@ -138,10 +138,6 @@ func generateHubCppRegistry(gen *protogen.Plugin, g *protogen.GeneratedFile, pro
 }
 
 const hubHpp = `#pragma once
-#include <google/protobuf/message.h>
-#include <google/protobuf/util/json_util.h>
-#include <tableau/protobuf/tableau.pb.h>
-
 #include <ctime>
 #include <functional>
 #include <mutex>
@@ -290,12 +286,6 @@ void Registry::Register() {
 
 const hubCppHeader = `#include "hub.pc.h"
 
-#include <google/protobuf/stubs/logging.h>
-#include <google/protobuf/stubs/status.h>
-#include <google/protobuf/text_format.h>
-
-#include <string>
-
 #include "logger.pc.h"
 #include "messager.pc.h"
 #include "util.pc.h"`
diff --git a/test/cpp-tableau-loader/src/CMakeLists.txt b/test/cpp-tableau-loader/src/CMakeLists.txt
index d8f72795..b827e3d4 100644
--- a/test/cpp-tableau-loader/src/CMakeLists.txt
+++ b/test/cpp-tableau-loader/src/CMakeLists.txt
@@ -22,7 +22,7 @@ if (MSVC)
     if(USE_CPP17)
         SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /DNDEBUG /std:c++17")
     else()
-        SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /DNDEBUG /std:c++11")
+        SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /DNDEBUG")
     endif()
 else()
     if(USE_CPP17)
diff --git a/test/cpp-tableau-loader/src/protoconf/hub.pc.cc b/test/cpp-tableau-loader/src/protoconf/hub.pc.cc
index a39c0353..c4339b8a 100644
--- a/test/cpp-tableau-loader/src/protoconf/hub.pc.cc
+++ b/test/cpp-tableau-loader/src/protoconf/hub.pc.cc
@@ -5,12 +5,6 @@
 
 #include "hub.pc.h"
 
-#include <google/protobuf/stubs/logging.h>
-#include <google/protobuf/stubs/status.h>
-#include <google/protobuf/text_format.h>
-
-#include <string>
-
 #include "logger.pc.h"
 #include "messager.pc.h"
 #include "util.pc.h"
diff --git a/test/cpp-tableau-loader/src/protoconf/hub.pc.h b/test/cpp-tableau-loader/src/protoconf/hub.pc.h
index 62fa5779..72c1593f 100644
--- a/test/cpp-tableau-loader/src/protoconf/hub.pc.h
+++ b/test/cpp-tableau-loader/src/protoconf/hub.pc.h
@@ -4,10 +4,6 @@
 // - protoc                        v3.19.3
 
 #pragma once
-#include <google/protobuf/message.h>
-#include <google/protobuf/util/json_util.h>
-#include <tableau/protobuf/tableau.pb.h>
-
 #include <ctime>
 #include <functional>
 #include <mutex>
diff --git a/test/cpp-tableau-loader/src/protoconf/load.pc.cc b/test/cpp-tableau-loader/src/protoconf/load.pc.cc
index fa46ea5c..90e3ee39 100644
--- a/test/cpp-tableau-loader/src/protoconf/load.pc.cc
+++ b/test/cpp-tableau-loader/src/protoconf/load.pc.cc
@@ -5,6 +5,10 @@
 
 #include "load.pc.h"
 
+#if __cplusplus >= 201703L
+#include <filesystem>
+#endif
+
 #include "logger.pc.h"
 #include "util.pc.h"
 
@@ -180,8 +184,13 @@ bool LoadMessageWithPatch(google::protobuf::Message& msg, const std::string& pat
     // patch path specified in PatchPaths, then use it instead of PatchDirs.
     patch_paths = iter->second;
   } else {
+    std::string filename = name + util::Format2Ext(fmt);
     for (auto&& patch_dir : options->patch_dirs) {
-      patch_paths.emplace_back(patch_dir + name + util::Format2Ext(fmt));
+#if __cplusplus >= 201703L
+      patch_paths.emplace_back((std::filesystem::path(patch_dir) / filename).make_preferred().string());
+#else
+      patch_paths.emplace_back(patch_dir + kPathSeperator + filename);
+#endif
     }
   }
 
@@ -281,7 +290,12 @@ bool LoadMessage(google::protobuf::Message& msg, const std::string& dir, Format
     }
   }
   if (path.empty()) {
-    path = dir + name + util::Format2Ext(fmt);
+    std::string filename = name + util::Format2Ext(fmt);
+#if __cplusplus >= 201703L
+    path = (std::filesystem::path(dir) / filename).make_preferred().string();
+#else
+    path = dir + kPathSeperator + filename;
+#endif
   }
 
   const google::protobuf::Descriptor* descriptor = msg.GetDescriptor();
diff --git a/test/cpp-tableau-loader/src/protoconf/messager.pc.h b/test/cpp-tableau-loader/src/protoconf/messager.pc.h
index b7151709..c0f73bfc 100644
--- a/test/cpp-tableau-loader/src/protoconf/messager.pc.h
+++ b/test/cpp-tableau-loader/src/protoconf/messager.pc.h
@@ -6,6 +6,7 @@
 #pragma once
 #include <google/protobuf/message.h>
 
+#include <chrono>
 #include <functional>
 #include <string>
 
@@ -19,9 +20,6 @@ class Messager {
  public:
   struct Stats {
     std::chrono::microseconds duration;  // total load time consuming.
-    // TODO: crc32 of config file to decide whether changed or not
-    // std::string crc32;
-    // int64_t last_modified_time = 0; // unix timestamp
   };
 
  public:
diff --git a/test/cpp-tableau-loader/src/protoconf/util.pc.cc b/test/cpp-tableau-loader/src/protoconf/util.pc.cc
index 9266d816..1e92f206 100644
--- a/test/cpp-tableau-loader/src/protoconf/util.pc.cc
+++ b/test/cpp-tableau-loader/src/protoconf/util.pc.cc
@@ -14,7 +14,6 @@
 
 #if __cplusplus >= 201703L
 #include <filesystem>
-namespace fs = std::filesystem;
 #else
 #ifdef _WIN32
 #include <direct.h>
@@ -31,9 +30,6 @@ namespace fs = std::filesystem;
 namespace tableau {
 #ifdef _WIN32
 #define mkdir(path, mode) _mkdir(path)
-static constexpr char kPathSeperator = '\\';
-#else
-static constexpr char kPathSeperator = '/';
 #endif
 
 static thread_local std::string g_err_msg;
@@ -49,7 +45,7 @@ namespace util {
 int Mkdir(const std::string& path) {
 #if __cplusplus >= 201703L
   std::error_code ec;
-  if (!fs::create_directories(path, ec)) {
+  if (!std::filesystem::create_directories(path, ec)) {
     if (ec) {
       std::cerr << "system error: " << ec.message() << std::endl;
       return -1;
@@ -77,7 +73,7 @@ int Mkdir(const std::string& path) {
 
 std::string GetDir(const std::string& path) {
 #if __cplusplus >= 201703L
-  return fs::path(path).parent_path().string();
+  return std::filesystem::path(path).parent_path().string();
 #else
   size_t pos = path.find_last_of(kPathSeperator);
   if (pos != std::string::npos) {
@@ -89,7 +85,7 @@ std::string GetDir(const std::string& path) {
 
 bool ExistsFile(const std::string& filename) {
 #if __cplusplus >= 201703L
-  return fs::exists(filename);
+  return std::filesystem::exists(filename);
 #else
   std::ifstream file(filename);
   // returns true if the file exists and is accessible
@@ -142,14 +138,6 @@ const std::string& Format2Ext(Format fmt) {
   }
 }
 
-bool Message2JSON(const google::protobuf::Message& msg, std::string& json) {
-  google::protobuf::util::JsonPrintOptions options;
-  options.add_whitespace = true;
-  options.always_print_primitive_fields = true;
-  options.preserve_proto_field_names = true;
-  return google::protobuf::util::MessageToJsonString(msg, &json, options).ok();
-}
-
 bool JSON2Message(const std::string& json, google::protobuf::Message& msg, const LoadOptions* options /* = nullptr */) {
   google::protobuf::util::Status status;
   if (options != nullptr) {
diff --git a/test/cpp-tableau-loader/src/protoconf/util.pc.h b/test/cpp-tableau-loader/src/protoconf/util.pc.h
index 9d24149b..32b1b3d3 100644
--- a/test/cpp-tableau-loader/src/protoconf/util.pc.h
+++ b/test/cpp-tableau-loader/src/protoconf/util.pc.h
@@ -16,6 +16,15 @@ namespace tableau {
 const std::string& GetErrMsg();
 void SetErrMsg(const std::string& msg);
 
+#if __cplusplus < 201703L
+// Platform-specific path separator
+#ifdef _WIN32
+constexpr char kPathSeperator = '\\';
+#else
+constexpr char kPathSeperator = '/';
+#endif
+#endif
+
 enum class Format {
   kUnknown,
   kJSON,
@@ -78,7 +87,6 @@ Format Ext2Format(const std::string& ext);
 // and the error message can be obtained by GetErrMsg().
 const std::string& Format2Ext(Format fmt);
 
-bool Message2JSON(const google::protobuf::Message& msg, std::string& json);
 bool JSON2Message(const std::string& json, google::protobuf::Message& msg, const LoadOptions* options = nullptr);
 bool Text2Message(const std::string& text, google::protobuf::Message& msg);
 bool Bin2Message(const std::string& bin, google::protobuf::Message& msg);