diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 49216e03..ea588983 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -15,12 +15,12 @@ on:
 jobs:
   build:
     name: CI build
-    runs-on: macos-10.15
+    runs-on: macos-11
     steps:
       - name: checkout
         uses: actions/checkout@v2
-      - name: force Xcode 12.4
-        run: sudo xcode-select -switch /Applications/Xcode_12.4.app
+      - name: force Xcode 12.5.1
+        run: sudo xcode-select -switch /Applications/Xcode_12.5.1.app
       - name: setup
         run: exec ./.github/scripts/setup.sh
       - name: build