iTunes Digital Copy redemptions from non-4K Blu-rays appear to support 4K streaming on new...
While 4K films on iTunes are streaming-only, it appears that users may be able to upgrade their movie collection if they buy a physical Blu-ray copy that comes with an iTunes Digital Copy code, even if the Blu-ray is just 1080p HD.

Although the "Logan" Blu-ray was purchased in HD, the iTunes Digital Copy redemption shows available to stream in 4K.
Upon setting up the new Apple TV 4K, AppleInsider checked iTunes movie libraries and found that recently redeemed iTunes Digital Copy films are listed in the iTunes movie library as being 4K-resolution. This despite the fact that the Blu-rays in question were not 4K versions.
Notably, years ago iTunes Digital Copy redemptions only offered standard-definition versions of films via Apple's store when redeemed.
Such legacy redemptions have never been upgraded to high definition, let alone 4K. That remains the case with the Apple TV 4K -- older iTunes Digital Copy films remained available to stream in standard definition, even though HD copies are available to purchase on the iTunes store.
To that end, when accessed via the Apple TV, the iTunes library items do not show an HD icon.
But when loading up a digitally redeemed copy of the film "Logan" from 20th Century Fox, the copy owned in the iTunes library shows that it is, in fact, available for streaming 4K, as well as HD.

Unfortunately, it's impossible to tell whether or not the film itself is actually streaming in 4K quality, as tvOS on the Apple TV runs at 4K resolution at all times, regardless of the quality of the content being played.
Further, although streamed programming may be available at resolutions up to 4K, the ability to reach that high of quality is largely dependent on the user's home internet connection.
Still, the appearance of a 4K icon on an iTunes Digital Copy obtained from a non-4K Blu-ray would strongly suggest that users can actually stream higher quality versions of films than were purchased on a physical disc. That's noteworthy because 4K Blu-rays not only require special players, but the discs themselves also carry a premium over standard HD Blu-rays, sometimes $10 to $15 more.
Given that Apple worked out a deal with studios to charge the same $20 price for films, whether they are 4K or HD, it would appear that iTunes will treat both 4K and HD the same -- as long as streaming is concerned. Downloads, however, remain limited to 1080p HD.

Although the "Logan" Blu-ray was purchased in HD, the iTunes Digital Copy redemption shows available to stream in 4K.
Upon setting up the new Apple TV 4K, AppleInsider checked iTunes movie libraries and found that recently redeemed iTunes Digital Copy films are listed in the iTunes movie library as being 4K-resolution. This despite the fact that the Blu-rays in question were not 4K versions.
Notably, years ago iTunes Digital Copy redemptions only offered standard-definition versions of films via Apple's store when redeemed.
Such legacy redemptions have never been upgraded to high definition, let alone 4K. That remains the case with the Apple TV 4K -- older iTunes Digital Copy films remained available to stream in standard definition, even though HD copies are available to purchase on the iTunes store.
To that end, when accessed via the Apple TV, the iTunes library items do not show an HD icon.
But when loading up a digitally redeemed copy of the film "Logan" from 20th Century Fox, the copy owned in the iTunes library shows that it is, in fact, available for streaming 4K, as well as HD.

Unfortunately, it's impossible to tell whether or not the film itself is actually streaming in 4K quality, as tvOS on the Apple TV runs at 4K resolution at all times, regardless of the quality of the content being played.
Further, although streamed programming may be available at resolutions up to 4K, the ability to reach that high of quality is largely dependent on the user's home internet connection.
Still, the appearance of a 4K icon on an iTunes Digital Copy obtained from a non-4K Blu-ray would strongly suggest that users can actually stream higher quality versions of films than were purchased on a physical disc. That's noteworthy because 4K Blu-rays not only require special players, but the discs themselves also carry a premium over standard HD Blu-rays, sometimes $10 to $15 more.
Given that Apple worked out a deal with studios to charge the same $20 price for films, whether they are 4K or HD, it would appear that iTunes will treat both 4K and HD the same -- as long as streaming is concerned. Downloads, however, remain limited to 1080p HD.
Comments
I'm sure there's a reason, but it's hard to imagine what it might be. And BECAUSE it's hard to imagine, I gotta figure it has something to do with the studios.
I also can't stand the marketing where they show something like "DVD + Digital." Have DVDs and Blurays become analog by some sort of magic now?
At the time I opined that choosing Ultraviolet over iTunes was going to bite them on the ass someday. Now I wonder if the number of people still buying movies is too small for the studios to give any thought at all to anything other than streaming services.
Strange that Disney has such a strong relationship with Apple, supports iTunes digital copies, and yet isn't offering 4K films on iTunes. I realize their 4K library is slim (just Guardians of the Galaxy 2), but why not offer that film in 4K?
What I find most perplexing is what seems to me to be an effort by Apple to push users towards cloud storage instead of local. It began with iTunes Match only downloading placeholders to my devices rather than the actual files. Now I can't download a 4K movie. How does Apple benefit from that? How do *I* benefit from that? What's the payoff?
I understand the benefit of centralized storage and delivery allowing users to easily access their content from any device. What I *don't* understand is why Apple would impose a barrier to those of us who prefer to store and manage content ourselves? The two approaches are not inherently mutually exclusive. Having the ability to download and manage files locally doesn't prevent Apple from offering the cloud method for those who prefer it.
Until now it's been possible to sacrifice the convenience of cloud delivery to gain the benefits of local storage. This move to prevent downloads of 4K content is a step away from that. Objections based on my preferences aside, I don't understand how this is a win for either Apple or users. What am I missing?