The first step of any upgrade should be to determine your current Ruby and Rails versions,

The first step of any upgrade should be to determine your current Ruby and Rails versions, then collect data about your code, test suite, and their dependencies. Part of your planning will be to decide what can be done before the upgrade and what can be put off until after. You always want to limit the scope of the changes, so when errors occur it is much simpler to nail down the change(s) that caused the errors.Note: We recommend migrating to new Rails conventions sooner rather than later. Too many teams choose to put off these migrations, which often means not coming back to them until they are forced by the next major Rails upgrade.