diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index c709f8c..e473627 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -17,7 +17,7 @@ jobs:
       matrix:
         #os: ['ubuntu-latest', 'windows-latest']
         os: ['ubuntu-latest']
-        ruby-version: ['2.3', '2.4', '2.7', '3.0', '3.1']
+        ruby-version: ['2.7', '3.0', '3.1']
 
     name: Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
     steps:
diff --git a/fluent-plugin-http-pull.gemspec b/fluent-plugin-http-pull.gemspec
index 41f727f..3a3fc6b 100644
--- a/fluent-plugin-http-pull.gemspec
+++ b/fluent-plugin-http-pull.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = test_files
   spec.require_paths = ["lib"]
 
-  spec.required_ruby_version = '>= 2.1'
+  spec.required_ruby_version = '>= 2.7'
 
   spec.add_development_dependency "rake", "~> 12.0"
   spec.add_development_dependency "simplecov", "~> 0.7"