watchOS 5.1.1 (build 16R6600) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-11-05T18:06:13Z. The update package is 148.07 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: c9d35c735b656e88942f2ba87f5d52b40b92c106.zip.