watchOS 5.1 (build 16R6591) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-10-30T17:20:58Z. The update package is 554.36 MB. This is a delta (partial) update that requires 5.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e96c92a4694a3c6f025551627acc60b03fedf8ef.zip.