tvOS 12.2.1 (build 16L250) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2019-04-10T17:06:54Z. The update package is 760.92 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ac22dae42a95b0daa2b33574e8ba930271864a0f.zip.