diff --git a/ipykernel/codeutil.py b/ipykernel/codeutil.py
deleted file mode 100644
index 08212a068..000000000
--- a/ipykernel/codeutil.py
+++ /dev/null
@@ -1,38 +0,0 @@
-"""Utilities to enable code objects to be pickled.
-
-Any process that import this module will be able to pickle code objects.  This
-includes the func_code attribute of any function.  Once unpickled, new
-functions can be built using new.function(code, globals()).  Eventually
-we need to automate all of this so that functions themselves can be pickled.
-
-Reference: A. Tremols, P Cogolo, "Python Cookbook," p 302-305
-"""
-
-# Copyright (c) IPython Development Team.
-# Distributed under the terms of the Modified BSD License.
-
-import warnings
-warnings.warn("ipykernel.codeutil is deprecated since IPykernel 4.3.1. It has moved to ipyparallel.serialize",
-    DeprecationWarning,
-    stacklevel=2
-)
-
-import copyreg
-import sys
-import types
-
-def code_ctor(*args):
-    return types.CodeType(*args)
-
-def reduce_code(co):
-    args =  [co.co_argcount, co.co_nlocals, co.co_stacksize,
-            co.co_flags, co.co_code, co.co_consts, co.co_names,
-            co.co_varnames, co.co_filename, co.co_name, co.co_firstlineno,
-            co.co_lnotab, co.co_freevars, co.co_cellvars]
-    if sys.version_info[0] >= 3:
-        args.insert(1, co.co_kwonlyargcount)
-    if sys.version_info > (3, 8, 0, 'alpha', 3):
-        args.insert(1, co.co_posonlyargcount)
-    return code_ctor, tuple(args)
-
-copyreg.pickle(types.CodeType, reduce_code)
diff --git a/ipykernel/pickleutil.py b/ipykernel/pickleutil.py
index 281b8f9ea..a2f3da11b 100644
--- a/ipykernel/pickleutil.py
+++ b/ipykernel/pickleutil.py
@@ -18,12 +18,7 @@
 from ipython_genutils.py3compat import buffer_to_bytes
 
 # This registers a hook when it's imported
-try:
-    # available since ipyparallel 5.1.1
-    from ipyparallel.serialize import codeutil
-except ImportError:
-    # Deprecated since ipykernel 4.3.1
-    from ipykernel import codeutil
+from ipyparallel.serialize import codeutil
 
 from traitlets.log import get_logger
 
diff --git a/ipykernel/tests/test_serialize.py b/ipykernel/tests/test_serialize.py
index 849f7208b..bee3a2641 100644
--- a/ipykernel/tests/test_serialize.py
+++ b/ipykernel/tests/test_serialize.py
@@ -6,9 +6,9 @@
 import pickle
 from collections import namedtuple
 
-from ipykernel.serialize import serialize_object, deserialize_object
+from ipyparallel.serialize import serialize_object, deserialize_object
 from IPython.testing import decorators as dec
-from ipykernel.pickleutil import CannedArray, CannedClass, interactive
+from ipyparallel.serialize.canning import CannedArray, CannedClass, interactive
 
 
 def roundtrip(obj):
diff --git a/setup.py b/setup.py
index f906aedbf..272cb043d 100644
--- a/setup.py
+++ b/setup.py
@@ -84,12 +84,13 @@ def run(self):
         'appnope;platform_system=="Darwin"',
     ],
     extras_require={
-        'test': [
-            'pytest !=5.3.4',
-            'pytest-cov',
-            'flaky',
-            'nose',  # nose because there are still a few nose.tools imports hanging around
-            'jedi<=0.17.2'
+        "test": [
+            "pytest !=5.3.4",
+            "pytest-cov",
+            "flaky",
+            "nose",  # nose because there are still a few nose.tools imports hanging around
+            "jedi<=0.17.2",
+            "ipyparallel",
         ],
     },
     classifiers=[