diff --git a/polly/docs/conf.py b/polly/docs/conf.py
index 699cc7c..8e16baa 100644
--- a/polly/docs/conf.py
+++ b/polly/docs/conf.py
@@ -49,9 +49,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '3.9'
+version = '4'
 # The full version, including alpha/beta/rc tags.
-release = '3.9'
+release = '4'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.