diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a2d4b05..f573d29 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -27,6 +27,8 @@ jobs:
             gemfile: gemfiles/rails_6.x_active_admin_3.x.gemfile
           - ruby-version: '3.0'
             gemfile: gemfiles/rails_7.x_active_admin_3.x.gemfile
+          - ruby-version: '4.0'
+            gemfile: gemfiles/rails_7.x_active_admin_3.x.gemfile
 
     env:
       BUNDLE_GEMFILE: ${{ matrix.gemfile }}
diff --git a/activeadmin-searchable_select.gemspec b/activeadmin-searchable_select.gemspec
index 664bd4f..c257d83 100644
--- a/activeadmin-searchable_select.gemspec
+++ b/activeadmin-searchable_select.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.files         = `git ls-files -z`.split("\x0")
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = ['>= 2.1', '< 4']
+  spec.required_ruby_version = '>= 2.1'
 
   spec.add_development_dependency 'bundler', ['>= 1.5', '< 3']
   spec.add_development_dependency 'rake'