watchOS 4.2 (build 15S5085b) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2017-10-30T22:07:26Z. The update package is 341.11 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: 05a01bbb743ac171bc0069929b426a1b92f412d1.zip.