diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 31f66fc..1478320 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -12,15 +12,37 @@ permissions:
 jobs:
   test:
     name: Specs
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        ruby-version: ['1.9.3', '2.0', '2.1', '2.2', '2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2']
+        ruby-version: ['2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3']
         channel: ['stable']
+        os: ['ubuntu-latest']
 
         include:
           - ruby-version: 'head'
             channel: 'experimental'
+            os: 'ubuntu-latest'
+
+          - ruby-version: '1.9.3'
+            channel: 'stable'
+            os: 'ubuntu-20.04'
+
+          - ruby-version: '2.0'
+            channel: 'stable'
+            os: ubuntu-20.04
+
+          - ruby-version: '2.1'
+            channel: 'stable'
+            os: 'ubuntu-20.04'
+
+          - ruby-version: '2.2'
+            channel: 'stable'
+            os: 'ubuntu-20.04'
+
+          - ruby-version: '2.3'
+            channel: 'stable'
+            os: 'ubuntu-20.04'
 
     continue-on-error: ${{ matrix.channel != 'stable' }}