tvOS 12.1.2 (build 16K5534a) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2019-01-07T18:15:35Z. The update package is 35.3 MB. This is a delta (partial) update that requires 12.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e08e48caa1f1e6148f41e5279b9667108c93d3e3.zip.