diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index c771f649..015293df 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -19,17 +19,17 @@ concurrency:
 jobs:
   # The CI test job
   test:
-    name: ${{ matrix.gap-branch }}
+    name: ${{ matrix.gap-version }}
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        gap-branch:
-          - master
-          - stable-4.15
-          - stable-4.14
-          - stable-4.13
-          - stable-4.12
+        gap-version:
+          - 'devel'
+          - '4.15'
+          - '4.14'
+          - '4.13'
+          - '4.12'
 
     steps:
       - uses: actions/checkout@v6
@@ -37,14 +37,24 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install polymake singular graphviz
-      - uses: gap-actions/setup-gap@v2
+      - uses: gap-actions/setup-gap@v3
         with:
-          GAP_PKGS_TO_CLONE: "polymaking hapcryst" # We need >= 0.8.4 and 0.1.13 to support polymake 4.0
-          GAP_PKGS_TO_BUILD: "io profiling nq"
-          GAPBRANCH: ${{ matrix.gap-branch }}
-      - uses: gap-actions/build-pkg@v1
-      - uses: gap-actions/run-pkg-tests@v3
-      - uses: gap-actions/process-coverage@v2
+          gap-version: ${{ matrix.gap-version }}
+      - shell: bash
+        run: |
+          # Install GAP packages via PackageManager
+          gap -c 'LoadPackage("PackageManager");
+                    InstallPackage("polymaking");
+                    InstallPackage("hapcryst");
+                    InstallPackage("nq");
+                    InstallPackage("io");
+                    QUIT;'
+      - uses: gap-actions/build-pkg@v2
+      - uses: gap-actions/run-pkg-tests@v4
+      #- uses: gap-actions/run-pkg-tests@v4
+      #  with:
+      #    mode: onlyneeded  # FIXME: disabled because the tests depend on too many optional packages
+      - uses: gap-actions/process-coverage@v3
       - uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/PackageInfo.g b/PackageInfo.g
index 1d558c01..a9c474ed 100644
--- a/PackageInfo.g
+++ b/PackageInfo.g
@@ -72,6 +72,7 @@ SetPackageInfo( rec(
                              [ "aclib",      ">=1.1" ],
                              [ "nq",         ">=1.1" ],
                              [ "SmallGrp",   ">=1.1" ],
+                             [ "Polymaking", ">=0.8.4"],
                            ],
     SuggestedOtherPackages := [
                                [ "homology",    ">=0.0"   ], 
@@ -79,7 +80,6 @@ SetPackageInfo( rec(
                                [ "singular", ">=06.07.23" ],
                                [ "congruence", ">=0,0" ],
                                [ "HAPcryst", ">=0.1.0" ],
-                               [ "Polymaking", ">=0.8.4"],
                                [ "xmod", ">0.0" ],
                                [ "laguna", ">0.0"]
                               ],