diff --git a/cnvlib/_version.py b/cnvlib/_version.py
index 43e38a8b..99ed3022 100644
--- a/cnvlib/_version.py
+++ b/cnvlib/_version.py
@@ -1 +1 @@
-__version__ = "0.9.11"
+__version__ = "0.9.12.dev0"