diff --git a/.github/workflows/test-cells-conda.yml b/.github/workflows/test-cells-conda.yml
index 5dfb488..d26d758 100644
--- a/.github/workflows/test-cells-conda.yml
+++ b/.github/workflows/test-cells-conda.yml
@@ -40,6 +40,7 @@ jobs:
           miniforge-version: latest
           python-version: ${{ matrix.python-version }}
           channels: conda-forge
+          conda-remove-defaults: "true"
 
       - name: Install cppwg
         run: |
diff --git a/.github/workflows/test-cells-ubuntu.yml b/.github/workflows/test-cells-ubuntu.yml
index 0e8545a..15f713f 100644
--- a/.github/workflows/test-cells-ubuntu.yml
+++ b/.github/workflows/test-cells-ubuntu.yml
@@ -6,13 +6,22 @@ on:
     branches:
       - "**"
 
-concurrency:
-  group: test-cells-ubuntu-${{ github.ref }}
-  cancel-in-progress: true
-
 jobs:
   test-cells-ubuntu:
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-22.04", "ubuntu-24.04"]
+
+    concurrency:
+      group: test-cells-ubuntu-${{ github.ref }}-${{ matrix.os }}
+      cancel-in-progress: true
+
+    defaults:
+      run:
+        shell: bash -el {0} # -l needed to activate pipx
 
     steps:
       - name: Checkout
@@ -21,25 +30,39 @@ jobs:
       - name: Install system dependencies
         run: |
           sudo apt-get update
+
+          for vtk_ver in $(seq 7 9); do
+            available=1
+            dpkg -s "libvtk${vtk_ver}-dev" || available=0
+            if [ "${available}" -eq 1 ]; then
+              break
+            fi
+          done
+          echo "VTK version: ${vtk_ver}"
+
           sudo apt-get install \
             cmake \
             git \
             libboost-all-dev \
-            libpetsc-real3.15 \
-            libpetsc-real3.15-dbg \
-            libpetsc-real3.15-dev \
-            libvtk9-dev \
+            libpetsc-real-dev \
+            libvtk${vtk_ver}-dev \
             mpi-default-bin \
-            mpi-default-dev \
+            mpi-default-dev
+
+          petsc_ver=$(dpkg-query -W -f='${Version}' libpetsc-real-dev | grep -oE '^[0-9]+\.[0-9]+')
+          echo "PETSc version: ${petsc_ver}"
+
+          sudo apt-get install \
+            pipx \
             python3-mpi4py \
-            python3-petsc4py-real3.15 \
-            python3-vtk9 \
-            vtk9
+            python3-petsc4py-real${petsc_ver} \
+            python3-pip \
+            python3-vtk${vtk_ver}
+
+          pipx ensurepath
 
       - name: Install cppwg
-        run: |
-          python -m pip install --upgrade pip
-          python -m pip install .
+        run: pipx install .
 
       - name: Configure
         run: |
@@ -61,9 +84,9 @@ jobs:
         working-directory: examples/cells
 
       - name: Build
-        run: python -m pip install -v .
+        run: PIP_BREAK_SYSTEM_PACKAGES=1 python3 -m pip install --user -v .
         working-directory: examples/cells
 
       - name: Test
-        run: python -m unittest discover tests
+        run: python3 -m unittest discover tests
         working-directory: examples/cells