watchOS 4.2 (build 15S5090c) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2017-11-06T18:03:49Z. The update package is 74.92 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: 5a163dd3cfd1692f68dace0a0d2cbd6a0c6d3f86.zip.