It’s not often that I agree with a headline containing the word “finally”, but it feels apt here. Juli Clover, MacRumors:
iTunes 12.6 introduces a “Rent once, watch anywhere” feature that lets iTunes users watch iTunes movie rentals across all devices with iOS 10.3 or tvOS 10.2.
Prior to this update, an iTunes movie was only available on a single device at a time. When a movie rented on a Mac was transferred to an iPhone, iPad, or iPod using USB, the movie became unavailable from an iTunes library until returned to the Mac.
A movie rented on an iOS device or an Apple TV was not previously watchable on other devices and could not be transferred between devices.
Basically, a rental is now attached to an account rather than a device. It doesn’t really matter whether the nine year delay in introducing this is the fault of Apple or movie studios, the fact is that it was a crappy situation that I ran into more than once. I imagine others have run into the same issue, particularly if they started the rental on an iOS device, quite reasonably assuming that they could pick it up on their Apple TV later.
iOS 10.3 and tvOS 10.2 have not yet been released.