diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1fcf9ef1..d3ba6908 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,6 +34,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -103,6 +107,10 @@ jobs:
         java: [temurin@11]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -244,6 +252,10 @@ jobs:
         java: [temurin@11]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -301,6 +313,10 @@ jobs:
         java: [temurin@11]
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Install sbt
+        if: contains(runner.os, 'macos')
+        run: brew install sbt
+
       - name: Checkout current branch (full)
         uses: actions/checkout@v4
         with:
@@ -324,7 +340,7 @@ jobs:
 
       - name: Publish site
         if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main'
-        uses: peaceiris/actions-gh-pages@v3.9.3
+        uses: peaceiris/actions-gh-pages@v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: site/target/docs/site