diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 18f8862..b19971a 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -1,25 +1,21 @@
 version: 2
 
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+  jobs:
+    pre_build:
+      - sphinx-apidoc -e -force --no-toc --module-first -o docs/source/api babelizer
+
 sphinx:
   builder: html
   configuration: docs/source/conf.py
   fail_on_warning: false
 
-formats:
-  - htmlzip
-
 python:
   install:
     - requirements: requirements-docs.txt
     - requirements: requirements.txt
     - method: pip
       path: .
-  system_packages: false
-
-build:
-  os: ubuntu-22.04
-  tools:
-    python: "3.9"
-  jobs:
-    pre_build:
-      - sphinx-apidoc -e -force --no-toc --module-first -o docs/source/api babelizer
diff --git a/news/93.doc b/news/93.doc
new file mode 100644
index 0000000..9091305
--- /dev/null
+++ b/news/93.doc
@@ -0,0 +1,3 @@
+
+Removed the the now-obsolete `system_packages` configuration key that was
+causing builds to fail on rtfd.io.