Somehow, Apple went until 2017 before adding one of the most basic features to iTunes. You see, for the past nine years, when you'd rent a movie via the app, you'd have to watch it on the device the rental originated from. So, if you rented Manchester by the Sea on your commute, watched a few minutes and then wanted to finish bumming yourself out on your big screen at home, you were out of luck. With the latest version of iTunes (12.6) and "rent once, watch anywhere," that's changed.