diff --git a/.readthedocs.yml b/.readthedocs.yml
index 3d34451371..3112b64ccc 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,7 +1,11 @@
 version: 2
 
 build:
-  image: latest
+  os: ubuntu-20.04
+  apt_packages:
+    - graphviz
+  tools:
+    python: "3.9"
 
 sphinx:
   builder: html
@@ -9,7 +13,6 @@ sphinx:
   fail_on_warning: true
 
 python:
-  version: 3.8
   system_packages: false
   install:
     - method: pip
@@ -17,4 +20,5 @@ python:
       extra_requirements:
         - docs
 
+# Don't build any extra formats
 formats: []