diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index a652300..8764aa8 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -23,6 +23,7 @@ jobs:
           - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,   r: 'release'}
           - {os: ubuntu-latest,   r: 'oldrel-1'}
+          - {os: ubuntu-latest,   r: '4.0.4'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}