At FastRuby.io, we recommend using the Dual Boot technique for upgrades. This requires us to generate a Gemfile.next.lock file that will be used to boot the app with the next version or Rails. In this article we’ll share 2 techniques to generate this file: the faster one and the safer one.

In this article I will explain how you can dual boot your application in your local environment and your continuous integration (CI) service. I hope that this will help you get ready for the next stable release of Rails.