diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 5c7c3f5..48b09fa 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -4,13 +4,18 @@ on: [ push, pull_request ]
 jobs:
   test:
     name: Test (Ruby ${{ matrix.ruby }})
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-${{ matrix.ubuntu }}
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '2.0', '2.1', '2.2', '2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', 'jruby', 'truffleruby' ]
+        ruby: [ '2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', 'jruby', 'truffleruby' ]
+        ubuntu: [ latest ]
+        include:
+          - { ruby: '2.0', ubuntu: '20.04' }
+          - { ruby: '2.1', ubuntu: '20.04' }
+          - { ruby: '2.2', ubuntu: '20.04' }
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}