diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b935cd7..6874a628 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Mindee Python API Library Changelog
 
+## v4.21.1 - 2025-04-28
+### Fixes
+* :bug: fix for Python 3.10 and lower: server uses 'Z' in date string
+
+
 ## v4.21.0 - 2025-04-16
 ### Changes
 * :sparkles: add support for RAG parameter in workflow executions (#319)
diff --git a/mindee/versions.py b/mindee/versions.py
index 42870617..e4eb76a8 100644
--- a/mindee/versions.py
+++ b/mindee/versions.py
@@ -1,6 +1,6 @@
 import sys
 
-__version__ = "4.21.0"
+__version__ = "4.21.1"
 
 PYTHON_VERSION = f"{sys.version_info[0]}.{sys.version_info[1]}"
 
@@ -12,7 +12,8 @@ def get_platform() -> str:
         "win32": "windows",
         "darwin": "macos",
         "aix": "aix",
-        "freebsd": "freebsd",
+        "freebsd": "bsd",
+        "openbsd": "bsd",
     }
     for name, agent_name in platforms.items():
         if sys.platform.startswith(name):