diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index f834edd..7e5ac22 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -36,9 +36,9 @@ jobs:
 
           - {os: windows-latest, r: 'release'}
 
-          - {os: ubuntu-18.04,   r: 'devel', http-user-agent: 'release'}
-          - {os: ubuntu-18.04,   r: 'release'}
-          - {os: ubuntu-18.04,   r: 'oldrel-1'}
+          - {os: ubuntu-latest,  r: 'devel'}
+          - {os: ubuntu-latest,  r: 'release'}
+          - {os: ubuntu-latest,  r: 'oldrel'}
 
     env:
       R_KEEP_PKG_SOURCE: yes