diff --git a/IPython/core/release.py b/IPython/core/release.py
index cab25ce..f05ce61 100644
--- a/IPython/core/release.py
+++ b/IPython/core/release.py
@@ -22,7 +22,7 @@ name = 'ipython'
 _version_major = 4
 _version_minor = 0
 _version_patch = 0
-_version_extra = 'b1'
+_version_extra = 'dev'
 # _version_extra = 'rc1'
 # _version_extra = ''  # Uncomment this for full releases