diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5eafeb0..d21a66f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-2019]
-        ruby: ['2.6', '2.7', '3.0', '3.1', '3.2', '3.3']
+        ruby: ['3.0', '3.1', '3.2', '3.3', 'head', 'truffleruby-head']
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
diff --git a/rubyntlm.gemspec b/rubyntlm.gemspec
index a75f322..c3406d9 100644
--- a/rubyntlm.gemspec
+++ b/rubyntlm.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.test_files    = s.files.grep(%r{^(test|spec|features)/})
   s.require_paths = ["lib"]
 
-  s.required_ruby_version = '>= 2.6.0'
+  s.required_ruby_version = '>= 3.0.0'
 
   s.license = 'MIT'