diff --git a/gambit/__init__.py b/gambit/__init__.py
index 37d56ed..b4635c8 100644
--- a/gambit/__init__.py
+++ b/gambit/__init__.py
@@ -5,5 +5,4 @@
 Author email: mjlumpe@gmail.com
 """
 
-__version__ = "0.4.0"
-
+__version__ = "0.4.0b1"