diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index e84b8bd..8d11a6b 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -9,7 +9,7 @@ version: 2
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.8"
+    python: "3.9"
   apt_packages:
     - graphviz