diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c4653ba..ec463ec 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,12 +8,16 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     steps:
       - uses: actions/checkout@v5
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: '3.13'
+          python-version: ${{ matrix.python-version }}
           cache: pip
       - run: pip install -r requirements-dev.txt
       - name: Byte-compile sources
diff --git a/readme.md b/readme.md
index 23a1833..89607a4 100644
--- a/readme.md
+++ b/readme.md
@@ -1,7 +1,7 @@
 # Castle demo application: Python
 
 This project demonstrates key Castle workflows in a Python / Flask app built on
-the [castle](https://github.com/castle/castle-python) SDK (7.1).
+the [castle](https://github.com/castle/castle-python) SDK (7.x).
 
 ## What's demonstrated
 
@@ -37,7 +37,7 @@ These are the only two values you need to configure.
 
 ## Running locally
 
-The castle 7.1 SDK requires **Python 3.9 or newer** (tested with Python 3.13).
+The castle 7.x SDK requires **Python 3.9 or newer**. This app is tested on Python 3.10–3.13.
 
 ```bash
 git clone https://github.com/castle/castle-python-example.git