Unless you're still on ruby 1.8 (long in the tooth), I don't see how ruby apps from newer versions of ruby will have any trouble integrating with other apps. I

Unless you're still on ruby 1.8 (long in the tooth), I don't see how ruby apps from newer versions of ruby will have any trouble integrating with other apps. I can understand a 2.1 app not working on 1.9 or 2.0 in some cases, but backwards compatibility is not the problem. Forwards compatibility is not really a feature of any mainstream language that I know of. I'm really saddened that there are IT departments that mandate system ruby, though. There isn't even a system ruby on Windows.