diff --git a/CHANGES.rst b/CHANGES.rst
index 22ab345..242669b 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -2,6 +2,12 @@
 Changes
 =======
 
+1.2.3 (unreleased)
+------------------
+
+- Nothing changed yet.
+
+
 1.2.2 (2024-05-30)
 ------------------
 
diff --git a/setup.py b/setup.py
index 7f5df9f..d15ef0e 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@ def read_file(name):
         return f.read()
 
 
-version = '1.2.2'
+version = '1.2.3.dev0'
 shortdesc = "Building data structures as node trees"
 longdesc = '\n\n'.join([read_file(name) for name in [
     'README.rst',