Although Apple TV 4K has changed little compared to set top box Fourth generation, the feature that lets you play videos in 4K and with HDR support has excited a lot of people who have been waiting for it for a long time.
But anyone who has tried to consume content in this very high resolution knows that there is a cost to be paid for good quality: I mean internet connection, which really needs to be very good for the video to play without any gagging.
This makes many people then prefer to download the entire content and then watch it all in a good way. The bad news is that, according to Apple's official page, won't be able to download 4K content on new Apple TV, just do streaming their.
You can download a local copy of an HD movie and you might be able to download HDR and Dolby Vision versions, but you won't be able to download a 4K version.
This means your connection needs to be really good so you can have the best experience with Apple TV 4K. Ma still recommends a minimum speed of 25Mbps to make a transmission in the blessed resolution. If the connection is not good enough, the device will automatically identify and switch to a lower quality.
The exact reason for this choice is unknown, but as well remembered the MacRumors, there are two plausible possibilities: the first has to do with the 4K file size, which is usually quite heavy and would take up a lot of space on Apple TV. Another possibility would have to do with the titles license today is to buy the titles in 4K for the same value as the HD resolution, but say the bad language that the studios would want to charge more for it.
Anyway, always good to prepare for this kind of setback. If you intend to buy the new set top box, make sure your internet conforms to the minimum requirement for playing such content.