diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f6002a2..4aabf2d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,27 +15,42 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  # macOS:
-  #   name: ${{ matrix.platform }} (Swift ${{ matrix.swift }})
-  #   runs-on: macos-12
-  #   strategy:
-  #     fail-fast: false
-  #     matrix:
-  #       platform:
-  #         - iOS
-  #         - macOS
-  #         - tvOS
-  #         - watchOS
-  #       swift:
-  #         - 5.5
-  #         - 5.6
-  #   steps:
-  #     - uses: actions/checkout@v2
-  #     - uses: mxcl/xcodebuild@v1
-  #       with:
-  #         platform: ${{ matrix.platform }}
-  #         swift: ~${{ matrix.swift }}
-  #         warnings-as-errors: true
+  macOS:
+    name: ${{ matrix.platform }} (Swift ${{ matrix.swift }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - macos-12
+        platform:
+          - iOS
+          - macOS
+          - tvOS
+          - watchOS
+        swift:
+          - 5.5
+          - 5.6
+        include:
+          - swift: 5.4
+            os: macos-11
+            platform: iOS
+          - swift: 5.4
+            os: macos-11
+            platform: macOS
+          - swift: 5.4
+            os: macos-11
+            platform: tvOS
+          - swift: 5.4
+            os: macos-11
+            platform: watchOS
+    steps:
+      - uses: actions/checkout@v2
+      - uses: mxcl/xcodebuild@v1
+        with:
+          platform: ${{ matrix.platform }}
+          swift: ~${{ matrix.swift }}
+          scheme: Builders
   linux:
     name: Linux (Swift ${{ matrix.swift }})
     runs-on: ubuntu-latest