If you’re running a Ruby on Rails application on a shared host, it’s super-double-plus recommended to freeze your Rails. Freezing your Rails means putting the framework into vendor/rails instead of floating with whatever gems that are installed on the host. Because if you do so, you’ll automatically be upgraded when they are. Not a great thing for a production application to have forced upon itself.

The great news is that this is silly simple. If you’re running 0.14.x or newer, you can simple do rake freeze_gems, and the current gems the system is used are unpacked into vendor/rails. Now the host can update as silly as it wants without affecting your application.