diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 43f82d2e..bb8e706b 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -1,5 +1,15 @@
+# .readthedocs.yml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
 version: 2
 
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.7"
+
 sphinx:
   configuration: documents/readthedoc/docs/source/conf.py