watchOS 5.1.1 (build 16R600) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-11-05T18:05:45Z. The update package is 962.04 MB. This is a delta (partial) update that requires 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: 33d88cea8f03adcc22c0661c27fdf6d520ec48c4.zip.