watchOS 5.1 (build 16R5589c) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-10-22T17:18:44Z. The update package is 734.02 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5fe0a10b81c8fdf1a85f53e8da3af34abfb1f220.zip.