diff --git a/.github/workflows/pytests-upstream.yml b/.github/workflows/pytests-upstream.yml
index a94ff3d0..05c99a5c 100644
--- a/.github/workflows/pytests-upstream.yml
+++ b/.github/workflows/pytests-upstream.yml
@@ -106,6 +106,7 @@ jobs:
       - name: Setup Micromamba ${{ matrix.python-version }}
         uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '1.5.10-0'
           environment-name: argopy-tests
           environment-file: ${{ env.CONDA_ENV_FILE }}
           init-shell: bash
@@ -232,6 +233,7 @@ jobs:
       - name: Setup Micromamba ${{ matrix.python-version }}
         uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '1.5.10-0'
           environment-name: argopy-tests
           environment-file: ${{ env.CONDA_ENV_FILE }}
           init-shell: bash
diff --git a/.github/workflows/pytests.yml b/.github/workflows/pytests.yml
index 0e582d8e..7cf10d1b 100644
--- a/.github/workflows/pytests.yml
+++ b/.github/workflows/pytests.yml
@@ -84,6 +84,7 @@ jobs:
       - name: Setup Micromamba ${{ matrix.python-version }}
         uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '1.5.10-0'
           environment-name: argopy-tests
           environment-file: ${{ env.CONDA_ENV_FILE }}
           init-shell: bash
@@ -206,6 +207,7 @@ jobs:
       - name: Setup Micromamba ${{ matrix.python-version }}
         uses: mamba-org/setup-micromamba@v1
         with:
+          micromamba-version: '1.5.10-0'
           environment-name: argopy-tests
           environment-file: ${{ env.CONDA_ENV_FILE }}
           init-shell: bash