watchOS 4.2.2 (build 15S5540a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-01-09T18:12:58Z. The update package is 145.99 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: f044c61df71d08bafbeceea12daf7ec263e86bc5.zip.