Reportedly, the latest version of the YouTube for Android app now supports 4K HDR playback even on lower resolution Android smartphone displays.
Smartphone displays are now pushing towards 2K and 4K resolutions. But that is limited to flagship devices. Mid-range devices are stuck with 720p or 1080p at max.
These lower-end display devices do not have the functionality of streaming YouTube videos in the highest possible resolution. Well, that is because of certain limitations of the device which include a slow connection, a low-res display, DRM, paywalled subscriptions, etc.
Even for Android devices that come with a 2K or 4K display, Google used to limit YouTube video streaming to 1440p on Android, although the videos were uploaded in 4K or more.
Thankfully, Google has addressed this issue, and you can now watch 2160p (4K) HDR videos on YouTube, even on 720p displays. 4K videos on 720p displays won't bring you much benefit, though, as hardware limitations are in place. It's even possible that Google made a mistake by allowing something like this.
FYI, this feature of watching the highest resolution on mobiles is already available for iOS users. With the latest update for YouTube, Android users will also join their iOS counterparts.
A server-side update for the YouTube Android app version 15.06.35 brings the new feature
As per reports, a server-side update is rolling out for all Android users. Specifically, this high-res streaming feature was spotted with YouTube app version 15.06.35. However, the latest reports confirm that the app version also does not matter now.
Personally, I have checked whether this feature is live on lower-res displays, and found the feature to be working pretty fine. Even HDR content was playing pretty smoothly.
With the latest build installed, if the video that a user wishes to watch is uploaded in 4K HDR, then both options will show up in the quality section.
Again, as already mentioned, this feature is available for any display. But it won't be much of use on lower-res displays, and you would simply waste your bandwidth.
The features first went live a few days ago on February 15, and now it seems like the new feature is available for everyone. Regardless of account, country, or app version, it is live across the globe.
If your YouTube app is not showing your high-res streaming options, then you can head over to Google Play Store to download the latest version of the YouTube for Android app on your phone.