In addition to IOS 10.3, Mac OS Sierra 10.12.4 Watch and OS 3.2, Apple Monday evening also sent out an update for the fourth generation Apple TV.
The only major news is that the scrolling function has been improved. Otherwise, the focus is on bugg- and security fixes.
To update your Apple TV, head to Settings -> General -> Update Software using the remote control. Note that it may take a while to complete the installation.