diff --git a/gemfiles/sinatra_14.gemfile b/gemfiles/sinatra_14.gemfile
index 481b006..05bdb4a 100644
--- a/gemfiles/sinatra_14.gemfile
+++ b/gemfiles/sinatra_14.gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'activerecord', '~> 3.2.0', :require => 'active_record'
+gem 'activerecord', '>= 4.0.0', :require => 'active_record'
 gem 'sinatra', '~> 1.4.0'
 gem 'rspec', '~> 2.14.1'