Apple has released iTunes 12.6, whose main feature is something that has been needed for many years:
Rent once, watch anywhere. Now you can enjoy iTunes movie rentals across your devices with iOS 10.3 or tvOS 10.2.
Rentals have always been a hassle. You had to move them from iTunes to a device, and if you rented a movie on the Apple TV, you couldn’t watch it on an iOS device.
However, Apple has not yet released iOS 10.3 or tvOS 10.2, but these should be out soon.
Get the iTunes update in the App Store app.