diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e87337a1b..01f0890da 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -155,18 +155,18 @@ jobs:
       matrix:
         include:
           - os: macos-latest
-            python-version: 3.9
+            python-version: "3.9"
             force-foolscap: false
           - os: windows-latest
-            python-version: 3.10
+            python-version: "3.9"
             force-foolscap: false
           # 22.04 has some issue with Tor at the moment:
           # https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3943
           - os: ubuntu-20.04
-            python-version: 3.8
+            python-version: "3.7"
             force-foolscap: true
           - os: ubuntu-20.04
-            python-version: 3.10
+            python-version: "3.9"
             force-foolscap: false
     steps: