watchOS 4.2 (build 15S5102b) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2017-11-17T18:17:30Z. The update package is 144.99 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: bb438fdd73594e2d8c8fdcee6c40be61e76932c8.zip.