diff --git a/notebook/_version.py b/notebook/_version.py
index bc030fd36..5a634ac2b 100644
--- a/notebook/_version.py
+++ b/notebook/_version.py
@@ -1,2 +1,2 @@
-version_info = (4, 1, 0, 'dev')
+version_info = (4, 1, 0, 'b1')
 __version__ = '.'.join(map(str, version_info))
diff --git a/notebook/static/base/js/namespace.js b/notebook/static/base/js/namespace.js
index 38056dbe1..94335ec04 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 = "4.1.0.dev";
+    Jupyter.version = "4.1.0.b1";
     Jupyter._target = '_blank';
     return Jupyter;
 });