diff --git a/mitmproxy/version.py b/mitmproxy/version.py
index 8b9b3eee3..5f6f3f07a 100644
--- a/mitmproxy/version.py
+++ b/mitmproxy/version.py
@@ -2,7 +2,7 @@ import os
 import subprocess
 import sys
 
-VERSION = "11.0.0"
+VERSION = "12.0.0.dev"
 MITMPROXY = "mitmproxy " + VERSION
 
 # Serialization format version. This is displayed nowhere, it just needs to be incremented by one