diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0c5fe4c..9f581fe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,26 +9,26 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ["3.0", "3.1", "3.2", "3.3", "3.4"]
+        ruby-version: ["3.0", "3.1", "3.2", "3.3", "3.4", "4.0"]
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby-version }}
           bundler-cache: true
       - name: Install dependencies
-        run: bundle install
+        run: bundle install --jobs 4 --retry 3
       - name: Run tests
         run: bundle exec rake spec
   lint:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4"
+          ruby-version: "4.0"
           bundler-cache: true
       - name: Install dependencies
         run: bundle install