diff --git a/.github/workflows/ubuntu-2004.yml b/.github/workflows/ubuntu-2004.yml
deleted file mode 100644
index 354fa2509..000000000
--- a/.github/workflows/ubuntu-2004.yml
+++ /dev/null
@@ -1,84 +0,0 @@
-name: Ubuntu 20.04
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - main
-      - "release/*"
-  pull_request:
-    types: [assigned, opened, synchronize, reopened, labeled]
-
-env:
-  UBUNTU_2004_IMAGE: "ghcr.io/gofractally/psibase-builder-ubuntu-2004:b70111acc20bdc6990e756a855fdbf428112c059"
-
-jobs:
-  ubuntu-2004-build:
-    name: Ubuntu 20.04 | Build
-    runs-on: ubuntu-latest
-    steps:
-      - name: Timestamp
-        id: ccache_cache_timestamp
-        run: echo timestamp=`date -u +"%Y-%m-%d-%H-%M-%S"` >>$GITHUB_OUTPUT
-      - name: Checkout
-        uses: actions/checkout@v3
-        with:
-          submodules: false
-          fetch-depth: 0
-      - name: Preserve ccache
-        uses: actions/cache@v3
-        with:
-          path: .caches
-          key: $ubuntu-20.04-caches-${{ steps.ccache_cache_timestamp.outputs.timestamp }}
-          restore-keys: |
-            $ubuntu-20.04-caches-
-      - name: Build
-        run: |
-          set -e
-          echo =====
-          mkdir -p $HOME/.ssh
-          chmod 700 $HOME/.ssh
-          git submodule update --init --recursive
-          echo =====
-          export CCACHE_DIR=${GITHUB_WORKSPACE}/.caches/ccache
-          export SCCACHE_DIR=${GITHUB_WORKSPACE}/.caches/sccache
-          export CCACHE_CONFIGPATH=${GITHUB_WORKSPACE}/ccache.conf
-          echo max_size = 600M >${GITHUB_WORKSPACE}/ccache.conf
-          echo log_file = ${GITHUB_WORKSPACE}/ccache.log >>${GITHUB_WORKSPACE}/ccache.conf
-          export SCCACHE_CACHE_SIZE=200M
-          export RUSTC_WRAPPER=sccache
-          export LLVM_CONFIG_PATH=/opt/clang+llvm-14.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/llvm-config
-          export LD_LIBRARY_PATH=/opt/clang+llvm-14.0.0-x86_64-linux-gnu-ubuntu-18.04/lib/
-          export DOCKER="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER -e LLVM_CONFIG_PATH -e LD_LIBRARY_PATH --user $(id -u):$(id -g) ${UBUNTU_2004_IMAGE}"
-          export DOCKER_ROOT="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER -e LLVM_CONFIG_PATH -e LD_LIBRARY_PATH ${UBUNTU_2004_IMAGE}"
-          docker pull ${UBUNTU_2004_IMAGE}
-          echo =====
-          ${DOCKER} ccache -s
-          echo =====
-          ${DOCKER} sccache -s
-          echo =====
-          mkdir build
-          ${DOCKER} bash -c "cd build && cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_RELEASE_WASM=yes -DBUILD_DEBUG_WASM=yes -DBUILD_DOC=yes -DCMAKE_CXX_COMPILER_LAUNCHER=ccache -DCMAKE_C_COMPILER_LAUNCHER=ccache .."
-          echo =====
-          ${DOCKER} bash -c "cd build && make -j $(nproc)"
-          echo =====
-          ${DOCKER} bash -c "cd build && ctest --output-on-failure -j $(nproc)"
-          echo =====
-          ls -la ${GITHUB_WORKSPACE}
-          echo =====
-          ${DOCKER} ccache -s
-          echo =====
-          ${DOCKER} sccache -s
-          echo =====
-          ${DOCKER} bash -c "cd build && cpack -G TGZ -D CPACK_PACKAGE_FILE_NAME=psidk-ubuntu-2004"
-          echo =====
-          ${DOCKER} bash -c "cd build && mv book psidk-book && tar czf ../psidk-book.tar.gz psidk-book"
-      - name: Upload psidk-ubuntu-2004
-        uses: actions/upload-artifact@v1
-        with:
-          name: psidk-ubuntu-2004
-          path: build/psidk-ubuntu-2004.tar.gz
-      - name: Upload psidk-book
-        uses: actions/upload-artifact@v1
-        with:
-          name: psidk-book
-          path: psidk-book.tar.gz
diff --git a/.github/workflows/ubuntu-2204.yml b/.github/workflows/ubuntu-builder.yml
similarity index 66%
rename from .github/workflows/ubuntu-2204.yml
rename to .github/workflows/ubuntu-builder.yml
index 99e694ded..f683c3421 100644
--- a/.github/workflows/ubuntu-2204.yml
+++ b/.github/workflows/ubuntu-builder.yml
@@ -1,20 +1,20 @@
-name: Ubuntu 22.04
+name: Ubuntu builds
+
 on:
   workflow_dispatch:
-  push:
-    branches:
-      - main
-      - "release/*"
-  pull_request:
-    types: [assigned, opened, synchronize, reopened, labeled]
-
-env:
-  UBUNTU_2204_IMAGE: "ghcr.io/gofractally/psibase-builder-ubuntu-2204:7e3c6e5739df95ba33943789d2cdf5472f91111a"
+  workflow_call:
 
 jobs:
-  ubuntu-2204-build:
-    name: Ubuntu 22.04 | Build
+  build:
+    name: Build
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - builder-image: "ghcr.io/${{ github.repository_owner }}/psibase-builder-ubuntu-2004:b70111acc20bdc6990e756a855fdbf428112c059"
+            ubuntu-version: "2004"
+          - builder-image: "ghcr.io/${{ github.repository_owner }}/psibase-builder-ubuntu-2204:7e3c6e5739df95ba33943789d2cdf5472f91111a"
+            ubuntu-version: "2204"
     steps:
       - name: Timestamp
         id: ccache_cache_timestamp
@@ -28,9 +28,9 @@ jobs:
         uses: actions/cache@v3
         with:
           path: .caches
-          key: $ubuntu-22.04-caches-${{ steps.ccache_cache_timestamp.outputs.timestamp }}
+          key: $ubuntu-${{ matrix.ubuntu-version }}-caches-${{ steps.ccache_cache_timestamp.outputs.timestamp }}
           restore-keys: |
-            $ubuntu-22.04-caches-
+            $ubuntu-${{ matrix.ubuntu-version }}-caches-
       - name: Build
         run: |
           set -e
@@ -46,9 +46,9 @@ jobs:
           echo log_file = ${GITHUB_WORKSPACE}/ccache.log >>${GITHUB_WORKSPACE}/ccache.conf
           export SCCACHE_CACHE_SIZE=200M
           export RUSTC_WRAPPER=sccache
-          export DOCKER="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER --user $(id -u):$(id -g) ${UBUNTU_2204_IMAGE}"
-          export DOCKER_ROOT="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER ${UBUNTU_2204_IMAGE}"
-          docker pull ${UBUNTU_2204_IMAGE}
+          export DOCKER="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER --user $(id -u):$(id -g) ${{ matrix.builder-image }}"
+          export DOCKER_ROOT="docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} -w ${GITHUB_WORKSPACE} -e CCACHE_DIR -e CCACHE_CONFIGPATH -e SCCACHE_DIR -e SCCACHE_CACHE_SIZE -e RUSTC_WRAPPER ${{ matrix.builder-image }}"
+          docker pull ${{ matrix.builder-image }}
           echo =====
           ${DOCKER} ccache -s
           echo =====
@@ -68,16 +68,16 @@ jobs:
           echo =====
           ${DOCKER} sccache -s
           echo =====
-          ${DOCKER} bash -c "cd build && cpack -G TGZ -D CPACK_PACKAGE_FILE_NAME=psidk-ubuntu-2204"
+          ${DOCKER} bash -c "cd build && cpack -G TGZ -D CPACK_PACKAGE_FILE_NAME=psidk-ubuntu-${{ matrix.ubuntu-version }}"
           echo =====
-          ${DOCKER} bash -c "cd build && mv book psidk-book && tar czf ../psidk-book.tar.gz psidk-book"
-      - name: Upload psidk-ubuntu-2204
+          ${DOCKER} bash -c "cd build && mv book psidk-book && tar czf ../psidk-book-${{ matrix.ubuntu-version }}.tar.gz psidk-book"
+      - name: Upload psidk-ubuntu-${{ matrix.ubuntu-version }}
         uses: actions/upload-artifact@v1
         with:
-          name: psidk-ubuntu-2204
-          path: build/psidk-ubuntu-2204.tar.gz
-      - name: Upload psidk-book
+          name: psidk-ubuntu-${{ matrix.ubuntu-version }}
+          path: build/psidk-ubuntu-${{ matrix.ubuntu-version }}.tar.gz
+      - name: Upload psidk-book-${{ matrix.ubuntu-version }}
         uses: actions/upload-artifact@v1
         with:
-          name: psidk-book
-          path: psidk-book.tar.gz
+          name: psidk-book-${{ matrix.ubuntu-version }}
+          path: psidk-book-${{ matrix.ubuntu-version }}.tar.gz