diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 7d39c01..2738f0c 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.6', '2.7', '3.0', '3.1', '3.2', 'jruby-head']
+        ruby-version: ['3.1', '3.2', '3.3', 'jruby-head']
 
     steps:
     - uses: actions/checkout@v2
diff --git a/README.md b/README.md
index 3370746..3dbf77b 100644
--- a/README.md
+++ b/README.md
@@ -15,8 +15,8 @@ https://github.com/omniauth/omniauth-saml
 
 ## Requirements
 
-* [OmniAuth](http://www.omniauth.org/) 1.3+
-* Ruby 2.4.x+
+* [OmniAuth](http://www.omniauth.org/) 2.1+
+* Ruby 3.1.x+
 
 ## Versioning
 
diff --git a/omniauth-saml.gemspec b/omniauth-saml.gemspec
index 92041fb..89cde5e 100644
--- a/omniauth-saml.gemspec
+++ b/omniauth-saml.gemspec
@@ -11,17 +11,17 @@ Gem::Specification.new do |gem|
   gem.email         = 'rajiv@alum.mit.edu'
   gem.homepage      = 'https://github.com/omniauth/omniauth-saml'
 
-  gem.required_ruby_version = '>= 2.4'
+  gem.required_ruby_version = '>= 3.1'
 
-  gem.add_runtime_dependency 'omniauth', '~> 2.0'
-  gem.add_runtime_dependency 'ruby-saml', '~> 1.12'
+  gem.add_runtime_dependency 'omniauth', '~> 2.1'
+  gem.add_runtime_dependency 'ruby-saml', '>= 1.17'
 
-  gem.add_development_dependency 'rake', '>= 12.3.3'
-  gem.add_development_dependency 'rspec', '~>3.4'
-  gem.add_development_dependency 'simplecov', '~> 0.11'
-  gem.add_development_dependency 'rack-test', '~> 0.6', '>= 0.6.3'
-  gem.add_development_dependency 'conventional-changelog', '~> 1.2'
-  gem.add_development_dependency 'coveralls', '>= 0.8.23'
+  gem.add_development_dependency 'rake', '~> 13.2'
+  gem.add_development_dependency 'rspec', '~> 3.13'
+  gem.add_development_dependency 'simplecov', '~> 0.10'
+  gem.add_development_dependency 'rack-test', '~> 2.1'
+  gem.add_development_dependency 'conventional-changelog', '~> 1.3'
+  gem.add_development_dependency 'coveralls', '~> 0.8'
 
   gem.files         = ['README.md', 'CHANGELOG.md', 'LICENSE.md'] + Dir['lib/**/*.rb']
   gem.test_files    = Dir['spec/**/*.rb']
diff --git a/spec/omniauth/strategies/saml_spec.rb b/spec/omniauth/strategies/saml_spec.rb
index 789b65e..25f4272 100644
--- a/spec/omniauth/strategies/saml_spec.rb
+++ b/spec/omniauth/strategies/saml_spec.rb
@@ -410,7 +410,7 @@ def test_default_relay_state(static_default_relay_state = nil, &block_default_re
 
     it 'should get SP metadata page' do
       expect(last_response.status).to eq 200
-      expect(last_response.header["Content-Type"]).to eq "application/xml"
+      expect(last_response.headers["Content-Type"]).to eq "application/xml"
     end
 
     it 'should configure attributes consuming service' do