watchOS 4.2.2 (build 15S5534a) is an official Apple over-the-air update for the Apple Watch (42mm), released on 2017-12-19T18:05:17Z. The update package is 148.2 MB. This is a delta (partial) update that requires 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: ea02d51ab47ad0594baff39a92f766b8b8e938e3.zip.