README.md in roadie-3.5.1 vs README.md in roadie-4.0.0

@@ -53,10 +53,10 @@
 ---------------
 
 [Add this gem to your Gemfile as recommended by Rubygems](http://rubygems.org/gems/roadie) and run `bundle install`.
 
 ```ruby
-gem 'roadie', '~> 3.5'
+gem 'roadie', '~> 4.0'
 ```
 
 You can then create a new instance of a Roadie document:
 
 ```ruby