diff --git a/spirit/__init__.py b/spirit/__init__.py
index 036d10ee..327982c8 100644
--- a/spirit/__init__.py
+++ b/spirit/__init__.py
@@ -2,4 +2,4 @@
 
 from __future__ import unicode_literals
 
-__version__ = '0.5.0'
+__version__ = '0.5.1dev'