diff --git a/.github/workflows/reusable-e2e.yml b/.github/workflows/reusable-e2e.yml
index 9a4156b8..c2cb08a8 100644
--- a/.github/workflows/reusable-e2e.yml
+++ b/.github/workflows/reusable-e2e.yml
@@ -14,14 +14,14 @@ jobs:
       fail-fast: false
       matrix:
         operating-system: [ ubuntu-latest, windows-latest, macos-latest ]
-        dotnet-version: [ '3.1', '5.0', '6.0', '7.0', '8.0' ]
+        dotnet-version: [ '3.1', '5.0', '6.0', '7.0', '8.0', '9.0' ]
     # macos-latest is ARM Runner, so .NET Core 3.1 and .NET 5 cannot be used.
     runs-on: ${{ (contains(fromJSON('["3.1", "5.0"]'), matrix.dotnet-version) && matrix.operating-system == 'macos-latest' && 'macos-13') || matrix.operating-system }}
     steps:
       - uses: actions/checkout@v4
         with:
           ref: ${{ inputs.branch || github.ref_name }}
-      - uses: actions/setup-dotnet@v3
+      - uses: actions/setup-dotnet@v4
         id: setup-dotnet
         with:
           dotnet-version: ${{ matrix.dotnet-version }}
diff --git a/README.md b/README.md
index 83932801..ca267947 100644
--- a/README.md
+++ b/README.md
@@ -167,7 +167,7 @@ jobs:
         id: setup-dotnet
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: '8.0.x' # [3.1.x, 5.0.x, 6.0.x, 7.0.x, 8.0.x]
+          dotnet-version: '9.0.x' # [3.1.x, 5.0.x, 6.0.x, 7.0.x, 8.0.x, 9.0.x]
       - name: Restore
         run: dotnet restore
       - name: Inspect code