diff --git a/.github/workflows/pythonbuild.yml b/.github/workflows/pythonbuild.yml
index a1bf4e5..b54cd27 100644
--- a/.github/workflows/pythonbuild.yml
+++ b/.github/workflows/pythonbuild.yml
@@ -20,7 +20,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install pytest hypothesis mypy Cython==3.0.2
+          pip install pytest hypothesis mypy Cython==3.0.3
 
       # The cythonized files allow installation from the sdist without cython
       - name: Generate cython
diff --git a/HISTORY.md b/HISTORY.md
index 0b7ebb3..b6047bb 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -4,6 +4,7 @@
 #### Changed
 - added keyword argument `pad` to Hamming distance. This controls whether sequences of different
   length should be padded or lead to a `ValueError`
+- upgrade to `Cython==3.0.3`
 
 ### v0.22.0
 #### Changed