diff --git a/README.md b/README.md
index a656cc9..a79c9a9 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ https://github.com/omniauth/omniauth-saml
 ## Requirements
 
 * [OmniAuth](http://www.omniauth.org/) 1.3+
-* Ruby 2.4.x+
+* Ruby 2.1.x+
 
 ## Versioning
 
diff --git a/omniauth-saml.gemspec b/omniauth-saml.gemspec
index 40be681..314347a 100644
--- a/omniauth-saml.gemspec
+++ b/omniauth-saml.gemspec
@@ -11,7 +11,7 @@ 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 = '>= 2.1'
 
   gem.add_runtime_dependency 'omniauth', '~> 1.3', '>= 1.3.2'
   gem.add_runtime_dependency 'ruby-saml', '~> 1.17'