diff --git a/modules/system/system.module b/modules/system/system.module
index 3a8cbeed7b3..0c7e34261c5 100644
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -6,7 +6,7 @@
  * Configuration system that lets administrators modify the workings of the site.
  */
 
-define('VERSION', '5.0');
+define('VERSION', '5.1-dev');
 
 /**
  * Implementation of hook_help().