watchOS 5.1.1 (build 16R6600) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2018-11-05T18:06:53Z. The update package is 112.72 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: c0f1908e407d154f2ca2b41bd39ea99392c61ba1.zip.