diff --git a/fsl/version.py b/fsl/version.py
index 9e07b662ca362e353e1f6eeeb23b5bf56fd813ca..182dbff4b4a69eedb225f2ad9ff709ea412c19cb 100644
--- a/fsl/version.py
+++ b/fsl/version.py
@@ -41,7 +41,7 @@ import            re
 import            string
 
 
-__version__ = '1.6.3'
+__version__ = '1.6.4'
 """Current version number, as a string. """