tvOS 11.2.5 (build 15K5539b) is an official Apple over-the-air update for the Apple TV 4 (2015), released on 2017-12-20T18:07:59Z. The update package is 55.77 MB. This is a delta (partial) update that requires 11.2.5 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 10cd0c351585e23b3f0fb4e521312063d6d2fce4.zip.