diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index de4ac23..e112739 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,21 +23,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.5", "2.6", "2.7", "3.0", "3.1", "3.2", "3.3", ruby-head, jruby-9.2, jruby-9.3]
+        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3", ruby-head, jruby-9.4]
         rubocop_version: ["0.92", "1.20", "1.66"]
         exclude:
-          - ruby: 2.5
-            rubocop_version: "1.66"
-          - ruby: 2.6
-            rubocop_version: "1.66"
           - ruby: ruby-head
             rubocop_version: "0.92"
           - ruby: ruby-head
             rubocop_version: "1.20"
-          - ruby: jruby-9.2
-            rubocop_version: "1.66"
-          - ruby: jruby-9.3
-            rubocop_version: "1.66"
 
     env:
       BUNDLE_GEMFILE: "gemfiles/rubocop_${{ matrix.rubocop_version }}.gemfile"
diff --git a/.rubocop.yml b/.rubocop.yml
index 51ec0be..cfbdb29 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,7 +5,7 @@ require:
 
 AllCops:
   DisplayCopNames: true
-  TargetRubyVersion: 2.5
+  TargetRubyVersion: 2.7
 
 Lint/RaiseException:
   Enabled: true
diff --git a/rubocop-thread_safety.gemspec b/rubocop-thread_safety.gemspec
index a645dd4..3dc2572 100644
--- a/rubocop-thread_safety.gemspec
+++ b/rubocop-thread_safety.gemspec
@@ -26,7 +26,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = '>= 2.5.0'
+  spec.required_ruby_version = '>= 2.7.0'
 
   spec.add_runtime_dependency 'rubocop', '>= 0.92.0'