diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6fb772e..99e35f7 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -47,6 +47,7 @@ jobs:
       - name: "Setup Micromamba"
         uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '1.5.6-0'
           environment-file: environment.yml
           environment-name: pontibus
           create-args: >-