diff --git a/authorizenet.gemspec b/authorizenet.gemspec
index 685fc43..0051c22 100644
--- a/authorizenet.gemspec
+++ b/authorizenet.gemspec
@@ -14,7 +14,11 @@ Gem::Specification.new do |s|
   s.required_ruby_version     = '>= 2.1.0'
   s.required_rubygems_version = '>= 1.3.6'
 
-  s.add_runtime_dependency 'activesupport', '= 4.2.6'
+  if RUBY_VERSION  < '2.2'
+    s.add_runtime_dependency 'activesupport', '= 4.2.6'
+  else
+    s.add_runtime_dependency 'activesupport', '>= 4.2.6'
+  end
   s.add_runtime_dependency 'nokogiri', '~> 1.6', '>= 1.6.4'
   s.add_runtime_dependency "roxml", "= 3.3.1"