diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cbdf812..35d48a8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,6 +15,14 @@ permissions:
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      # Floor + latest. The floor is the version setup.py's `python_requires`
+      # promises (>=3.12): a promise nothing runs is how 1.0.0 and both release
+      # candidates shipped a Requires-Python they had never tested. Keep this in
+      # step with templates/setup.mustache in the factory.
+      matrix:
+        python-version: ["3.12", "3.14"]
     steps:
       - uses: actions/checkout@v5
 
@@ -31,7 +39,7 @@ jobs:
       - uses: actions/setup-python@v6
         if: steps.detect.outputs.has_pkg == 'true'
         with:
-          python-version: "3.14"
+          python-version: ${{ matrix.python-version }}
 
       - name: Install
         if: steps.detect.outputs.has_pkg == 'true'