diff --git a/thinc/about.py b/thinc/about.py
index 98ef7bb49..8c54de3d8 100644
--- a/thinc/about.py
+++ b/thinc/about.py
@@ -1,2 +1,2 @@
-__version__ = "9.1.0"
+__version__ = "9.1.1.dev0"
 __release__ = True