diff --git a/CHANGES.rst b/CHANGES.rst
index 0d950206..f23a7eb8 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,12 @@
 Changelog
 =========
 
+5.1 (unreleased)
+----------------
+
+- Nothing changed yet.
+
+
 5.0.1 (2019-06-17)
 ------------------
 
diff --git a/setup.py b/setup.py
index ca2fb293..44146b0b 100644
--- a/setup.py
+++ b/setup.py
@@ -16,7 +16,7 @@
 
 setup(
     name='Products.ZCatalog',
-    version='5.0.1',
+    version='5.1.dev0',
     url='https://github.com/zopefoundation/Products.ZCatalog',
     license='ZPL 2.1',
     description="Zope's indexing and search solution.",