watchOS 4.2 (build 15S102) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2017-12-05T18:01:21Z. The update package is 572.61 MB. This is a delta (partial) update that requires 3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 020e49f21e91b05f591fc3dce12a833685f2198d.zip.