diff --git a/.github/workflows/pythonapp.yml b/.github/workflows/pythonapp.yml
index 87c1e06..195dbc7 100644
--- a/.github/workflows/pythonapp.yml
+++ b/.github/workflows/pythonapp.yml
@@ -17,7 +17,7 @@ jobs:
         fail-fast: false
         matrix:
             os: [
-              macos-latest, 
+              macos-13, 
               windows-latest, 
               ubuntu-latest
             ]