watchOS 4.2 (build 15S5085b) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2017-10-30T22:07:39Z. The update package is 153.44 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: c8dc32f0da9ed2698e577737958a7ce0673a9d99.zip.