https://wccftech.com/tvos-13-3-1-update-for-apple-tv-now-available-for-download/

Apple TV users can now download tvOS 13.3.1 update for Apple TV HD and Apple TV 4K. tvOS 13.3.1 IPSW for Apple TV HD is also available.

The latest tvOS 13.3.1 update for both Apple TV HD and Apple TV 4K is now available for download and it's available over the air for users the world over. While we do not have a changelog for this update, but it's safe to assume that this is nothing more than a bug fix update, nothing more.