diff --git a/.rubocop.yml b/.rubocop.yml
index d65f8a9..69f0be5 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -3,7 +3,7 @@ plugins:
   - rubocop-rake
 
 AllCops:
-  TargetRubyVersion: 3.2
+  TargetRubyVersion: 4.0.5
   NewCops: enable
   SuggestExtensions: false
 
diff --git a/bitsmithy-auth.gemspec b/bitsmithy-auth.gemspec
index 77b1022..e72b1c0 100644
--- a/bitsmithy-auth.gemspec
+++ b/bitsmithy-auth.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
                      "a mountable engine for the default sign-in flow."
   spec.homepage = "https://github.com/bitsmithy/auth-ruby"
   spec.license = "MIT"
-  spec.required_ruby_version = ">= 3.2.0"
+  spec.required_ruby_version = ">= 4.0.5"
   # Private gem — consumed via `gem 'bitsmithy-auth', github: 'bitsmithy/auth-ruby'`.
   # If switching to GitHub Packages or a private gem server, set allowed_push_host below.
   # spec.metadata["allowed_push_host"] = "https://rubygems.pkg.github.com/bitsmithy"