watchOS 5.1 (build 16R5584a) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-10-15T17:09:24Z. The update package is 119.29 MB. This is a delta (partial) update that requires 5.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 98b498d232a491abe8e52b285c2ff86fe70fcb77.zip.