diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index bbfbf53..bcc7d7b 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -32,6 +32,8 @@ jobs:
           profile: minimal
           toolchain: 1.81.0
           default: true
+      - name: Select Xcode 15.4
+        run: sudo xcode-select -s /Applications/Xcode_15.4.app
       - name: Build Automerge XCFramework and library
         if: steps.cache-automerge.outputs.cache-hit != 'true'
         run: ./scripts/build-xcframework.sh
@@ -46,11 +48,13 @@ jobs:
             libuniffi_automerge.a
             libuniffi_automerge_threads.a
 
-  test-automerge-swift:
+  mac:
     runs-on: macos-14
     needs: automerge-dependencies
     steps:
       - uses: actions/checkout@v4
+      - name: Select Xcode 15.4
+        run: sudo xcode-select -s /Applications/Xcode_15.4.app
       - name: Restore Automerge XCFramework and library
         uses: actions/cache/restore@v4
         with:
@@ -65,7 +69,7 @@ jobs:
       - name: Swift tests
         run: swift test
 
-  test-automerge-wasm:
+  wasm:
     runs-on: ubuntu-latest
     needs: automerge-dependencies
     strategy: