diff --git a/.ruby-version b/.ruby-version
index 7bcbb380..c5106e6d 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.4.9
+4.0.4
diff --git a/Gemfile b/Gemfile
index e86e602a..8affa4a1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source "https://rubygems.org"
-ruby "3.4.9"
+ruby "4.0.4"
 
 gem "jekyll", ">= 4.4.1"
 gem "html-proofer", ">= 3.10.0"