watchOS 4.2 (build 15S5090c) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2017-11-06T18:03:09Z. The update package is 342.63 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: 7da772b8c1a876a6ab3f4d897887cf77cd80c49f.zip.