tvOS 11.2.1 (build 15K152) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2017-12-13T18:31:02Z. The update package is 308.87 MB. This is a delta (partial) update that requires 11.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: eb117a1ef82e10d6b33360652009ddc742088fa1.zip.