diff --git a/README.md b/README.md
index b8d1c2e..a3bf0c7 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,9 @@ Help support Gdspy development by [donating via PayPal](https://www.paypal.com/c
 
 ## History of changes
 
+### Version 1.6.4 (Apr 23, 2021)
+* Fix missing module import (thanks Troy Tamas for the fix).
+
 ### Version 1.6.3 (Dec 28, 2020)
 * Fix bounding box edge case (thanks Troy Tamas for the fix).
 
diff --git a/gdspy/__init__.py b/gdspy/__init__.py
index 96b603e..b16eed4 100644
--- a/gdspy/__init__.py
+++ b/gdspy/__init__.py
@@ -19,7 +19,7 @@
 - http://www.buchanan1.net/stream_description.html
 """
 
-__version__ = "1.6.3"
+__version__ = "1.6.4"
 
 import warnings