diff --git a/.github/workflows/build-book-pullrequest.yaml b/.github/workflows/build-book-pullrequest.yaml
index acc7db39..2119eb7b 100644
--- a/.github/workflows/build-book-pullrequest.yaml
+++ b/.github/workflows/build-book-pullrequest.yaml
@@ -32,7 +32,7 @@ jobs:
         shell: bash -l {0}
     steps:
       - name: checkout files in repo
-        uses: actions/checkout@main
+        uses: actions/checkout@v3
       - name: remove Dockerfile
         run: |
           rm binder/Dockerfile
@@ -45,6 +45,7 @@ jobs:
           DOCKER_REGISTRY: "ghcr.io"
           PUBLIC_REGISTRY_CHECK: true
           APPENDIX_FILE: "binder/appendix.txt"
+          REPO2DOCKER_EXTRA_ARGS: --Repo2Docker.base_image=docker.io/library/buildpack-deps:bionic
       - name: list docker images
         run: |
           docker image ls -a
diff --git a/.github/workflows/build-book.yaml b/.github/workflows/build-book.yaml
index 345c616d..f3d36cac 100644
--- a/.github/workflows/build-book.yaml
+++ b/.github/workflows/build-book.yaml
@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout files in repo
-        uses: actions/checkout@main
+        uses: actions/checkout@v3
       - name: remove Dockerfile
         run: |
           rm binder/Dockerfile
@@ -53,7 +53,7 @@ jobs:
       run:
         shell: bash -l {0}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v3
       - name: Build the book
         run: |
           # copy baltrad notebooks to book dir