diff --git a/.readthedocs.yml b/.readthedocs.yml
index 5bb171afa..7d5f1c206 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,5 +1,7 @@
 version: 2
 
+formats: all
+
 python:
   version: 3.7
   install: