diff --git a/.github/workflows/jekyll-build.yml b/.github/workflows/jekyll-build.yml
index e002f7ee..af5a7315 100644
--- a/.github/workflows/jekyll-build.yml
+++ b/.github/workflows/jekyll-build.yml
@@ -182,7 +182,7 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@4c56a21280b36d862b5fc31348f463d60bdc55d5  # v1.301.0
         with:
-          ruby-version: '3.3'
+          ruby-version: '4.0.2'
 
       - name: Install dependencies
         run: bundle install
diff --git a/Dockerfile b/Dockerfile
index db4c50d8..5dade89a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:3.3-bookworm AS base
+FROM ruby:4.0-bookworm AS base
 
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]