watchOS 5.1 (build 16R5568d) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-10-02T17:14:20Z. The update package is 466.22 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: bf4cddf819130623a65b8f5ff1655f60a486612a.zip.