diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ba38dd9..f0fd440 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: [3.2, 3.3, 3.4]
+        ruby-version: [3.2, 3.3, 3.4, 4.0]
     steps:
       - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
diff --git a/email_address.gemspec b/email_address.gemspec
index 728c2ea..2e32245 100644
--- a/email_address.gemspec
+++ b/email_address.gemspec
@@ -12,7 +12,7 @@ Gem::Specification.new do |spec|
   spec.homepage = "https://github.com/afair/email_address"
   spec.license = "MIT"
 
-  spec.required_ruby_version = ">= 2.5", "< 4"
+  spec.required_ruby_version = ">= 2.5", "< 4.1"
   spec.files = `git ls-files`.split($/)
   spec.executables = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]