Apple operating system updates day! This time, it is for Apple TVs of fourth generation and 4K: the tvOS 12.1 (build 16J602) has just been released for everyone.
There is no clear information on what this update brings to Apple TV, other than general improvements and bug fixes. TvOS 12, launched in mid-September, arrived with support for Dolby Atmos and some new screensavers.
As always, the latest tvOS can be obtained from Settings »System» Software Update. If you paint any details about version 12.1, we will update this post.