diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9221302..960f4f5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,7 +36,7 @@ jobs:
             xcode: 14.3.1 # Swift 5.8
             sim: iPhone 14
           - os: macos-13
-            xcode: 15.0 # Swift 5.9
+            xcode: '15.0' # Swift 5.9
             sim: iPhone 15
     runs-on: ${{ matrix.os }}
     steps: