diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 16e7b00..14fcefd 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -13,10 +13,10 @@ jobs:
   ci:
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/tillitis/tkey-builder:3
+      image: ghcr.io/tillitis/tkey-builder:4
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           # fetch-depth: 0
           persist-credentials: false
diff --git a/contrib/Dockerfile b/contrib/Dockerfile
index 3f3d73b..f00f4ec 100644
--- a/contrib/Dockerfile
+++ b/contrib/Dockerfile
@@ -42,7 +42,7 @@ RUN apt-get -qq update -y \
                vim \
                xdot \
                sdcc \
-               splint \               
+               splint \
                cmake \
                gcc-arm-none-eabi \
                libnewlib-arm-none-eabi \
diff --git a/contrib/Makefile b/contrib/Makefile
index d9aa7b1..e38a0ce 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -5,7 +5,7 @@
 BUILDIMAGE=tkey-builder-local
 
 # default image used when running a container
-IMAGE=ghcr.io/tillitis/tkey-builder:3
+IMAGE=ghcr.io/tillitis/tkey-builder:4
 
 all:
 	@echo "Targets:"