tvOS 12.1 (build 16J602) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2018-10-30T17:14:33Z. The update package is 662.33 MB. This is a delta (partial) update that requires 11.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e6e8b34599dbe4dfc4bf8021f778107509671891.zip.