diff --git a/.ruby-version b/.ruby-version
index 7bcbb38..d13e837 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.4.9
+4.0.6
diff --git a/Gemfile b/Gemfile
index d610f97..0b204ff 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-ruby '3.4.9'
+ruby '4.0.6'
 
 # core
 gem 'eventmachine', '~> 1.2.7'