No outward facing changes were announced. So more than likely, the update features small changes and bug fixes.
The minor update arrives exactly one week after tvOS 15.1. That update brought support for SharePlay, allowing you to use FaceTime and watch movies or TV shows with friends and family no matter where they are.
The software will automatically be downloaded to a Apple TV HD or Apple TV 4K.
If you haven’t already enabled automatic updates, you can download the software by heading to Settings > System > Software Updates > Update Software. Right the button to update software is the toggle switch to turn on automatic updates.