watchOS 4.2 (build 15S102) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2017-12-05T18:01:29Z. The update package is 145.43 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: 7ae2f4b1921dc6c9c5c9e570ad32ba115538c268.zip.