Darrell Etherington, writing for TechCrunch:
Apple is now selling and renting digital 4K movies via iTunes, in addition to its HD and SD resolution versions. The addition of 4K content, which you can stream as well as download, is mainly designed to support the new Apple TV, which supports 4K HDR output for the first time. Plus, if you bought HD versions of titles for which 4K HDR is available, Apple is automatically upgrading them for free.
This is a key piece of Apple’s incentive puzzle for getting users to upgrade to a new Apple TV, as it means there will be a strong content pool that users can access right away. Apple will also be able to take advantage of 4K streaming content provided via Netflix, which has offered both 4K and HDR streaming on other platforms for a while now, and Amazon Prime Video, which is finally arriving on the platform as previously announced.
As someone who owns a ton of iTunes content, I couldn’t be more thrilled with this. This would be like Sony saying “FREE BLU-RAYS FOR EVERYONE!” when the HD transition first happened. It’s insane.
That said, it seems as though 4K-specific remasters that are released separately will not be included in this offer (e.g. the new Close Encounters of the Third Kind). We’ll see how things shake out when the new Apple TV launches, but I’m optimistic about the necessity of double dipping (or lack thereof).