watchOS 5.1.1 (build 16R6600) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-11-05T18:05:42Z. The update package is 67.57 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: b09a9cd5bdf00248056c98ba2260f0b5021021f0.zip.