watchOS 4.2 (build 15S5090c) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2017-11-06T18:03:38Z. The update package is 69.39 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7302c4bcde823bfd07430229efc206f4adc18c29.zip.