diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 794ca85..bc3f30b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,13 +8,13 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-13]
         pyver: ["3.8", "3.9", "3.10", "3.11"]
     steps:
       - uses: actions/checkout@v3
       - uses: mamba-org/setup-micromamba@v1
         with:
-          micromamba-version: '1.3.1-0'
+          micromamba-version: '1.5.6-0'
           environment-name: test-env
           create-args: >-
             python=${{ matrix.pyver }}