watchOS 5.1 (build 16R5577c) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-10-09T17:11:46Z. The update package is 733.95 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: db1767c37383b4b8c96f91468dbb0f12de4397d3.zip.