One of the most underrated announcements in the Apple Spring loaded event is the new Apple TV screen calibration feature for the new Apple TV 4K.
The premise is that you can customize the color profile of the connected TV by specifying the actual depth sensor from your iPhone.
If it is found to be incorrect, the connected Apple TV will get the correct color profile and adjust the image on the TV.
9to5Mac now reports that the screen calibration function is also compatible with the older version of Apple TV that belongs to Apple TV.
For 2015 HD, you need the latest tvOS 14.5 (expected next week) and an iPhone with Face ID enabled, and iOS 14.5 for calibration.
After the process is complete, the connected Apple TV will select the best color profile based on the readings and apply it to any content on the Apple TV, but not other content on the TV.
According to 9to5Mac, the corrected colors look warmer and more natural, although this process does not work on Dolby Vision TVs.