diff --git a/atest/DynamicTypesAnnotationsLibrary.py b/atest/DynamicTypesAnnotationsLibrary.py
index a46056b..659e262 100644
--- a/atest/DynamicTypesAnnotationsLibrary.py
+++ b/atest/DynamicTypesAnnotationsLibrary.py
@@ -148,3 +148,7 @@ def enum_conversion(self, param: Optional[penum] = None):
     def keyword_with_deco_and_signature(self, arg1: bool = False, arg2: bool = False):
         """Test me doc here"""
         return f"{arg1}: {type(arg1)}, {arg2}: {type(arg2)}"
+
+    @keyword
+    def keyword_optional_with_none(self, arg: Optional[str] = None):
+        return f"arg: {arg}, type: {type(arg)}"
diff --git a/atest/tests_types.robot b/atest/tests_types.robot
index 139d983..436c8c0 100644
--- a/atest/tests_types.robot
+++ b/atest/tests_types.robot
@@ -1,5 +1,6 @@
 *** Settings ***
 Library        DynamicTypesLibrary.py
+Library        DynamicTypesAnnotationsLibrary.py    xxx
 Suite Setup    Import DynamicTypesAnnotationsLibrary In Python 3 Only
 
 *** Test Cases ***
@@ -73,6 +74,16 @@ Enum Conversion To Invalid Value Should Fail
     Run Keyword And Expect Error    ValueError: Argument 'param' got value 'not ok' that*
     ...    Enum Conversion    not ok
 
+Type Conversion With Optional And None
+    ${types} =    Keyword Optional With None
+    Should Contain    ${types}    arg: None,
+    Should Contain    ${types}    <class 'NoneType'>
+    ${types} =    Keyword Optional With None    None
+    Should Contain    ${types}    arg: None,
+    Should Contain    ${types}    <class 'str'>
+    ${types} =    Keyword Optional With None    ${None}
+    Should Contain    ${types}    arg: None,
+    Should Contain    ${types}    <class 'NoneType'>
 
 *** Keywords ***
 Import DynamicTypesAnnotationsLibrary In Python 3 Only
diff --git a/src/robotlibcore.py b/src/robotlibcore.py
index 47d2b06..bbfeb4d 100644
--- a/src/robotlibcore.py
+++ b/src/robotlibcore.py
@@ -18,19 +18,17 @@
 examples see the project pages at
 https://github.com/robotframework/PythonLibCore
 """
-
 import inspect
 import os
+import typing
 
+from robot import __version__ as robot_version
 from robot.utils import PY_VERSION
 
-try:
-    import typing
-except ImportError:
-    typing = None
 
 from robot.api.deco import keyword  # noqa F401
 
+RF32 = robot_version < '4.'
 
 __version__ = '2.2.2.dev1'
 
@@ -246,8 +244,10 @@ def _get_typing_hints(cls, function):
             # remove return and self statements
             if arg_with_hint not in all_args:
                 hints.pop(arg_with_hint)
-        default = cls._get_defaults(arg_spec)
-        return cls._remove_optional_none_type_hints(hints, default)
+        if RF32:
+            default = cls._get_defaults(arg_spec)
+            return cls._remove_optional_none_type_hints(hints, default)
+        return hints
 
     @classmethod
     def _args_as_list(cls, function, arg_spec):
@@ -260,6 +260,7 @@ def _args_as_list(cls, function, arg_spec):
             function_args.append(arg_spec.varkw)
         return function_args
 
+    # TODO: Remove when support RF 3.2 is dropped
     # Copied from: robot.running.arguments.argumentparser
     @classmethod
     def _remove_optional_none_type_hints(cls, type_hints, defaults):
@@ -274,6 +275,7 @@ def _remove_optional_none_type_hints(cls, type_hints, defaults):
                         type_hints[arg] = types[0]
         return type_hints
 
+    # TODO: Remove when support RF 3.2 is dropped
     # Copied from: robot.running.arguments.argumentparser
     @classmethod
     def _is_union(cls, typing_type):
diff --git a/utest/test_get_keyword_types.py b/utest/test_get_keyword_types.py
index f377d04..d5cd917 100644
--- a/utest/test_get_keyword_types.py
+++ b/utest/test_get_keyword_types.py
@@ -1,6 +1,9 @@
-from typing import List, Union
-
 import pytest
+import typing
+
+from robotlibcore import RF32
+
+from typing import List, Union
 
 from DynamicTypesAnnotationsLibrary import DynamicTypesAnnotationsLibrary
 from DynamicTypesAnnotationsLibrary import CustomObject
@@ -180,3 +183,15 @@ def test_keyword_self_and_keyword_only_types(lib_types):
 def test_keyword_with_decorator_arguments(lib_types):
     types = lib_types.get_keyword_types('keyword_with_deco_and_signature')
     assert types == {'arg1': bool, 'arg2': bool}
+
+
+@pytest.mark.skipif(RF32, reason='Only for RF4+')
+def test_keyword_optional_with_none_rf4(lib_types):
+    types = lib_types.get_keyword_types('keyword_optional_with_none')
+    assert types == {'arg': typing.Union[str, type(None)]}
+
+
+@pytest.mark.skipif(not RF32, reason='Only for RF3.2+')
+def test_keyword_optional_with_none_rf32(lib_types):
+    types = lib_types.get_keyword_types('keyword_optional_with_none')
+    assert types == {'arg': str}
diff --git a/utest/test_keyword_builder.py b/utest/test_keyword_builder.py
index f66e653..eb956ee 100644
--- a/utest/test_keyword_builder.py
+++ b/utest/test_keyword_builder.py
@@ -1,6 +1,7 @@
 import pytest
+import typing
 
-from robotlibcore import KeywordBuilder
+from robotlibcore import KeywordBuilder, RF32
 from moc_library import MockLibrary
 from DynamicTypesAnnotationsLibrary import DynamicTypesAnnotationsLibrary
 
@@ -77,11 +78,18 @@ def test_types(lib):
     assert spec.argument_types == {'varargs': int, 'other': bool, 'kwargs': int}
 
 
-def test_optional_none(lib):
+@pytest.mark.skipif(not RF32, reason='Only for RF3.2+')
+def test_optional_none_rf32(lib):
     spec = KeywordBuilder.build(lib.optional_none)
     assert spec.argument_types == {'arg1': str, 'arg2': str}
 
 
+@pytest.mark.skipif(RF32, reason='Only for RF4')
+def test_optional_none_rf4(lib):
+    spec = KeywordBuilder.build(lib.optional_none)
+    assert spec.argument_types == {'arg1': typing.Union[str, None], 'arg2': typing.Union[str, None]}
+
+
 def test_complex_deco(dyn_types):
     spec = KeywordBuilder.build(dyn_types.keyword_with_deco_and_signature)
     assert spec.argument_types == {'arg1': bool, 'arg2': bool}