watchOS 4.2 (build 15S5102b) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2017-11-17T18:17:32Z. The update package is 1.09 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d3b9a2d53d6924b44490a1de4004b754349ac6a4.zip.