diff --git a/CHANGES.rst b/CHANGES.rst
index 591692d..144175f 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,6 +2,12 @@
  CHANGES
 =========
 
+4.0.1 (unreleased)
+==================
+
+- Nothing changed yet.
+
+
 4.0.0 (2017-05-16)
 ==================
 
diff --git a/setup.py b/setup.py
index df5a1a7..585ba56 100644
--- a/setup.py
+++ b/setup.py
@@ -27,7 +27,7 @@ def read(*rnames):
         return f.read()
 
 setup(name='zope.app.broken',
-      version='4.0.0',
+      version='4.0.1.dev0',
       author='Zope Corporation and Contributors',
       author_email='zope-dev@zope.org',
       description='Zope Broken (ZODB) Object Support',