watchOS 4.2.2 (build 15S5540a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-01-09T18:13:19Z. The update package is 35.4 MB. This is a delta (partial) update that requires 4.2.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 77c3c65b8d4f35474359f4dd91817426dfc7392f.zip.