diff --git a/Gemfile.activesupport32 b/Gemfile.activesupport32
index 8678900..a235641 100644
--- a/Gemfile.activesupport32
+++ b/Gemfile.activesupport32
@@ -1,4 +1,4 @@
 source "https://rubygems.org"
 gemspec
 
-gem 'activesupport', '~> 3.2'
+gem 'activesupport', '~> 4.2'
diff --git a/lib/time_difference.rb b/lib/time_difference.rb
index 73705cf..0d59947 100644
--- a/lib/time_difference.rb
+++ b/lib/time_difference.rb
@@ -1,5 +1,6 @@
 require 'rubygems'
-require "active_support/all"
+require "active_support"
+require "active_support/core_ext"
 
 class TimeDifference
 
diff --git a/time_difference.gemspec b/time_difference.gemspec
index c9b0692..7ac5adf 100644
--- a/time_difference.gemspec
+++ b/time_difference.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |gem|
   gem.version       = "0.4.2"
   gem.license = 'MIT'
 
-  gem.add_runtime_dependency('activesupport')
+  gem.add_runtime_dependency('activesupport', '~> 4.2' )
   gem.add_development_dependency('rspec', '~> 2.13.0')
   gem.add_development_dependency('rake')