diff --git a/readthedocs.yml b/readthedocs.yml
index 3a2617b3..767b9a99 100644
--- a/readthedocs.yml
+++ b/readthedocs.yml
@@ -1,5 +1,5 @@
 
-version: 2
+version: 5.1.1
 
 mkdocs:
   configuration: mkdocs.yml