diff --git a/.github/workflows/sphinx.yml b/.github/workflows/sphinx.yml
index be5d2e4..b251791 100644
--- a/.github/workflows/sphinx.yml
+++ b/.github/workflows/sphinx.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Build HTML
-      uses: ammaraskar/sphinx-action@main
+      uses: ammaraskar/sphinx-action@master
       with:
         pre-build-command: "pip3 install --user --ignore-installed sphinxcontrib-domaintools myst-parser furo sphinx>=6.0 sphinx_design sphinx-copybutton"
         docs-folder: .