diff --git a/.github/workflows/ci-tests.yml b/.github/workflows/ci-tests.yml
index 1426afcfba..4db83f98f2 100644
--- a/.github/workflows/ci-tests.yml
+++ b/.github/workflows/ci-tests.yml
@@ -68,14 +68,14 @@ jobs:
       - name: "data cache"
         uses: ./.github/workflows/composite/iris-data-cache
         with:
-          cache_build: 5
+          cache_build: 6
           env_name: ${{ env.ENV_NAME }}
           version: ${{ env.IRIS_TEST_DATA_VERSION }}
 
       - name: "conda package cache"
         uses: ./.github/workflows/composite/conda-pkg-cache
         with:
-          cache_build: 5
+          cache_build: 6
           cache_period: ${{ env.CACHE_PERIOD }}
           env_name: ${{ env.ENV_NAME }}
 
@@ -90,7 +90,7 @@ jobs:
       - name: "conda environment cache"
         uses: ./.github/workflows/composite/conda-env-cache
         with:
-          cache_build: 5
+          cache_build: 6
           cache_period: ${{ env.CACHE_PERIOD }}
           env_name: ${{ env.ENV_NAME }}
           install_packages: "cartopy nox pip"
@@ -103,14 +103,14 @@ jobs:
       - name: "cartopy cache"
         uses: ./.github/workflows/composite/cartopy-cache
         with:
-          cache_build: 5
+          cache_build: 6
           cache_period: ${{ env.CACHE_PERIOD }}
           env_name: ${{ env.ENV_NAME }}
 
       - name: "nox cache"
         uses: ./.github/workflows/composite/nox-cache
         with:
-          cache_build: 5
+          cache_build: 6
           env_name: ${{ env.ENV_NAME }}
           lock_file: ${{ env.LOCK_FILE }}