Initially reported on the MacRumors forums (via AppleInsider), it seems that some users have spotted recent films like Passenger and Fantastic Beasts and Where To Find Them had “4K” and “HDR” mentions in both owned and rented copies of either film. This led to other users checking their iTunes purchase history and confirming this listing.
However given that there is no actual 4K support on iTunes just yet, it seems that 4K and HDR are only mentioned in name, and that files downloaded are still in standard high-definition. However we have heard rumors that Apple could be preparing a 4K Apple TV for launch later this year.
There have also been signs to suggest that a new Apple TV device is in the works, thanks to developer logs, but whether or not this will bring 4K and HDR support remains to be seen, but given the listing in the iTunes purchase history, perhaps it will. We’re not sure when Apple will announce these changes, but the company does have an iPhone event coming up so perhaps we will learn more then.