diff --git a/.readthedocs.yml b/.readthedocs.yml
index 7fdaad96..ebdbdd63 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -2,13 +2,17 @@
 
 version: 2
 
+build:
+  os: "ubuntu-20.04"
+  tools:
+    python: "3.7"
+
 sphinx:
   configuration: WORC/doc/conf.py
 
 formats: []
 
 python:
-  version: 3.7
   install:
     - requirements: requirements.txt
     - method: pip