diff --git a/brew-cask-upgrade.gemspec b/brew-cask-upgrade.gemspec
index 31cb93d..723f401 100644
--- a/brew-cask-upgrade.gemspec
+++ b/brew-cask-upgrade.gemspec
@@ -13,7 +13,7 @@ Gem::Specification.new do |s|
 
   s.bindir      = "bin"
   s.executables = %w[brew-cask-upgrade]
-  s.required_ruby_version = "> 2.6.0"
+  s.required_ruby_version = "> 3.1.0"
   s.metadata = {
     "rubygems_mfa_required" => "true",
   }