diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 724dd87..dc41b9f 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -24,8 +24,9 @@ jobs:
           - {os: windows-latest,  r: '4.2'}
           - {os: windows-latest,  r: 'release'}
           - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
-          - {os: ubuntu-latest,   r: 'release'}
-          - {os: ubuntu-latest,   r: 'oldrel-1'}
+          - {os: ubuntu-24.04,   r: 'release'}
+          - {os: ubuntu-22.04,   r: 'oldrel-1'}
+          - {os: ubuntu-20.04,   r: 'oldrel-3'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}