diff --git a/.github/workflows/deploy-doc.yml b/.github/workflows/deploy-doc.yml
index 31eeb073..a113450d 100644
--- a/.github/workflows/deploy-doc.yml
+++ b/.github/workflows/deploy-doc.yml
@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
       - uses: ruby/setup-ruby@708024e6c902387ab41de36e1669e43b5ee7085e # v1.283.0
         with:
-          ruby-version: '4.0.1'
+          ruby-version: '3.4.8'
       - run: bundle install
       - name: Setup Pages
         uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 9e7fab3c..f2626700 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -23,7 +23,7 @@ jobs:
       - uses: ruby/setup-ruby@708024e6c902387ab41de36e1669e43b5ee7085e # v1.283.0
         with:
           bundler-cache: true
-          ruby-version: 4.0.1
+          ruby-version: 3.4.8
       - name: Update version file with the release version
         run: |
           if [ "${{ github.event_name }}" == "workflow_dispatch" ]; then
diff --git a/renovate.json5 b/renovate.json5
index b74d6cce..aee2f8a3 100644
--- a/renovate.json5
+++ b/renovate.json5
@@ -32,5 +32,13 @@
         '/line-openapi/',
       ],
     },
+    {
+      // Disable automatic Ruby version updates
+      // Language version updates should be handled manually
+      matchPackageNames: [
+        'ruby',
+      ],
+      enabled: false,
+    },
   ],
 }