watchOS 4.2 (build 15S5100a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2017-11-13T18:03:44Z. The update package is 343.02 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: 0504c26cca3cf16d9cb5c030faeb06852e7f72bb.zip.