diff --git a/CHANGES b/CHANGES
index 2de7816..b46839c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+blueox (0.11.6.4)
+  * Fix encoding of unknown types
+
 blueox (0.11.6.3)
   * Fix handling of unicode strings
 
diff --git a/blueox/__init__.py b/blueox/__init__.py
index 8cc8cfc..2f3fc36 100644
--- a/blueox/__init__.py
+++ b/blueox/__init__.py
@@ -9,7 +9,7 @@
 """
 
 __title__ = 'blueox'
-__version__ = '0.11.6.3'
+__version__ = '0.11.6.4'
 __author__ = 'Rhett Garber'
 __author_email__ = 'rhettg@gmail.com'
 __license__ = 'ISC'
diff --git a/blueox/utils.py b/blueox/utils.py
index 28d7a93..5a15b29 100644
--- a/blueox/utils.py
+++ b/blueox/utils.py
@@ -82,5 +82,4 @@ def msgpack_encode_default(obj):
         return time.mktime(obj.utctimetuple())
     if isinstance(obj, datetime.date):
         return obj.strftime("%Y-%m-%d")
-
-    raise TypeError("Unknown type: %r" % (obj,))
+    return None