diff --git a/.github/workflows/old.yml b/.github/workflows/old.yml
index 5ddb229..72f79c7 100644
--- a/.github/workflows/old.yml
+++ b/.github/workflows/old.yml
@@ -27,7 +27,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       # https://github.com/josephwright/siunitx/blob/549cad913591b92a3a199b7477a325866303bf29/.github/workflows/main.yaml
       # We need Ghostscript for XeTeX tests.
diff --git a/.github/workflows/prooftrees-autochecks.yml b/.github/workflows/prooftrees-autochecks.yml
index c0a298c..c84656c 100644
--- a/.github/workflows/prooftrees-autochecks.yml
+++ b/.github/workflows/prooftrees-autochecks.yml
@@ -39,7 +39,7 @@ jobs:
       cache_key: ${{ steps.texlive.outputs.cache_key }}
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Install TeX Live
         id: texlive
         uses: zauguin/install-texlive@v4
@@ -55,7 +55,7 @@ jobs:
       ctan_prooftrees_output: ${{ steps.build.outputs.ctan_ret }}
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Build ctan
         id: build 
         # uses: cfr42/nfssext/.github/actions/nfssext-autocheck-action@eeab7fc024553e35584805f40af881812b7e09a6