Apple released tvOS 10.1.1 for Apple TV (4th Generation) on Monday. Apple’s general release notes specify only that, “This update includes general performance and stability improvements.” The Security Content document for the update details eight security flaws that were patched.
Most of those security flaws would allow the bad guys to take over your Apple TV, assuming that’s a thing. While security updates are always important, the reality for this update is that Apple is fixing problems with code shared between its OSes.
You can download the update through Software Update on your Apple TV.