diff --git a/docs/CHANGES.txt b/docs/CHANGES.txt
index 0a7d2480..1527b36d 100644
--- a/docs/CHANGES.txt
+++ b/docs/CHANGES.txt
@@ -1,6 +1,12 @@
 Changelog
 =========
 
+4.3b1 (unreleased)
+------------------
+
+- Nothing changed yet.
+
+
 4.3a2 (2012-10-18)
 ------------------
 
diff --git a/setup.py b/setup.py
index 32b34a19..e3feaf2e 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup
 import os.path
 
-version = '4.3a2'
+version = '4.3b1.dev0'
 
 setup(name='Plone',
       version=version,