diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 83e8056..af6a0d8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ env:
 jobs:
   rubocop:
     name: Rubocop
-    runs-on: 'ubuntu-20.04'
+    runs-on: 'ubuntu-latest'
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
diff --git a/script/update_rubygems_and_install_bundler b/script/update_rubygems_and_install_bundler
index 264c8d7..1dfdc1b 100755
--- a/script/update_rubygems_and_install_bundler
+++ b/script/update_rubygems_and_install_bundler
@@ -2,6 +2,20 @@
 
 set -e
 
-echo "Installing latest rubygems / bundler"
-yes | gem update --system
-yes | gem install bundler
+function is_ruby_31_plus {
+  if ruby -e "exit(RUBY_VERSION.to_f >= 3.1)"; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+if is_ruby_31_plus; then
+  echo "Installing latest rubygems / bundler"
+  yes | gem update --system
+  yes | gem install bundler
+else
+  echo "Installing rubygems 3.2.22 / bundler 2.2.22"
+  yes | gem update --system '3.2.22'
+  yes | gem install bundler -v '2.2.22'
+fi