diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 1aba4da0..848f7a2f 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -6,9 +6,9 @@
 version: 2
 
 build:
-  os: ubuntu-20.04
+  os: ubuntu-22.04
   tools:
-    python: "3.9"
+    python: "3.11"
 
 sphinx:
    configuration: manual/conf.py
@@ -17,3 +17,7 @@ formats: all
 
 sphinx:
   fail_on_warning: true
+
+python:
+  install:
+    - requirements: manual/requirements.txt
diff --git a/manual/requirements.txt b/manual/requirements.txt
new file mode 100644
index 00000000..483a4e96
--- /dev/null
+++ b/manual/requirements.txt
@@ -0,0 +1 @@
+sphinx_rtd_theme