I use exact gem versions because experience shows that even minor gem updates can break the tutorial. (RSpec is particularly guilty of this.) I generally recomm

I use exact gem versions because experience shows that even minor gem updates can break the tutorial. (RSpec is particularly guilty of this.) I generally recommend '~>' for more advanced users, but when getting your bearings I think it's best to use exact versions. That said, I keep the Rails Tutorial and sample application as up-to-date as possible—and in fact both have already been updated with the latest version. :-) http://ruby.railstutorial.org/ruby-on-rails-tutorial-book#sec-install_rails http://ruby.railstutorial.org/ruby-on-rails-tutorial-book#se... $ gem install rails -v 3.2.12 https://github.com/railstutorial/sample_app_2nd_ed/blob/master/Gemfile https://github.com/railstutorial/sample_app_2nd_ed/blob/mast... gem 'rails', '3.2.12'