watchOS 5.1.1 (build 16R600) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-11-05T18:05:17Z. The update package is 977.18 MB. This is a delta (partial) update that requires 3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 142bad47c3f81238aed7779969f3c4b67dd4b880.zip.