diff --git a/.github/workflows/gh-pages.yml b/.github/workflows/gh-pages.yml
index 9b476eda..bb836b76 100644
--- a/.github/workflows/gh-pages.yml
+++ b/.github/workflows/gh-pages.yml
@@ -14,6 +14,10 @@ jobs:
         with:
           submodules: recursive
 
+      # needed for depext to work
+      - run: sudo apt-get update
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+
       - name: Use OCaml
         uses: ocaml/setup-ocaml@v2
         with: