watchOS 4.2 (build 15S5090c) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2017-11-06T18:03:39Z. The update package is 179.64 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: ec1cd943d3e6b692b5608bb5eb842a5c95561bf3.zip.