diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 1ef3a4257..997d65510 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -2,6 +2,16 @@
 Changelog
 *********
 
+4.0.6 -- 2026-05-07
+===================
+
+Fixes
+-----------
+* fix: Replace isinstance metaclass check with issubclass in generate_ecc_signing_key (#802)
+  `#802 <https://github.com/aws/aws-encryption-sdk-python/pull/802>`_
+* fix: use issubclass instead of isinstance in _set_signature_type (#800)
+  `#800 <https://github.com/aws/aws-encryption-sdk-python/pull/800>`_
+
 4.0.5 -- 2026-04-20
 ===================
 
diff --git a/src/aws_encryption_sdk/identifiers.py b/src/aws_encryption_sdk/identifiers.py
index 85cafef6a..c41e91811 100644
--- a/src/aws_encryption_sdk/identifiers.py
+++ b/src/aws_encryption_sdk/identifiers.py
@@ -17,7 +17,7 @@
     # We only actually need these imports when running the mypy checks
     pass
 
-__version__ = "4.0.5"
+__version__ = "4.0.6"
 USER_AGENT_SUFFIX = "AwsEncryptionSdkPython/{}".format(__version__)