diff --git a/setup.py b/setup.py
index 7d1e30ba..572d8875 100644
--- a/setup.py
+++ b/setup.py
@@ -41,7 +41,7 @@ import configparser
 # Take a look at https://www.python.org/dev/peps/pep-0440/
 # for a consistent versioning pattern.
 
-PSYCOPG_VERSION = '2.9.9'
+PSYCOPG_VERSION = '2.9.10.dev1'
 
 
 # note: if you are changing the list of supported Python version please fix