diff --git a/notebook/static/base/js/namespace.js b/notebook/static/base/js/namespace.js
index 5d5875157..af8a940f0 100644
--- a/notebook/static/base/js/namespace.js
+++ b/notebook/static/base/js/namespace.js
@@ -73,7 +73,7 @@ define(function(){
     // tree
     jglobal('SessionList','tree/js/sessionlist');
 
-    Jupyter.version = "5.1.0";
+    Jupyter.version = "5.1.0.dev";
     Jupyter._target = '_blank';
     return Jupyter;
 });