In the case of a Rails upgrade, that will mean every single piece of functionality in the application. Major and Minor versions are allowed to make changes to the public API, so this may cause errors in your application.Do yourself a favor and make sure your test coverage is good you start an upgrade. Patch versions only include bug fixes, and don't change any public API. Then run the Update task mentioned below to update configuration files, then run your tests.When changing Rails versions, it's best to move slowly, one minor version at a time, in order to make good use of the deprecation warnings. You can find a list of all released Rails versions here.Rails generally stays close to the latest released Ruby version when it's released: Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails.The best way to be sure that your application still works after upgrading is to have good test coverage before you start the process.If you don't have automated tests that exercise the bulk of your application, you'll need to spend time manually exercising all the parts that have changed.(enter "h" for help) [Ynaqdh] force config/conflict config/...Don't forget to review the difference, to see if there were any unexpected changes.
From Ruby on Rails 5.0 onwards, Ruby 2.2.2 is the only supported Ruby version.Make sure you are on Ruby 2.2.2 version or greater, before you proceed.In Rails 4.2, an Active Record model inherits from in Active Record and Active Model, then the entire callback chain is halted.In other words, successive 'before' callbacks are not executed, and neither is the action wrapped in callbacks.In Rails 5.0, returning in those kind of callbacks will still halt the callback chain, but you will receive a deprecation warning about this upcoming change.Before attempting to upgrade an existing application, you should be sure you have a good reason to upgrade.You need to balance several factors: the need for new features, the increasing difficulty of finding support for old code, and your available time and skills, to name a few.Constants in deeper places only executed at runtime, like regular method bodies, are also fine because the file defining them will have been eager loaded while booting.For the vast majority of applications this change needs no action.$ rails app:update identical config/exist config conflict config/Overwrite /myapp/config/routes.rb?(enter "h" for help) [Ynaqdh] force config/conflict config/Overwrite /myapp/config/application.rb?