watchOS 4.2 (build 15S5085b) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2017-10-30T22:07:32Z. The update package is 218.48 MB. This is a delta (partial) update that requires 4.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6e47370ae9c5de475b6bf269bd8f611f6682c7a1.zip.