watchOS 5.1.2 (build 16S5042a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2018-11-07T21:15:21Z. The update package is 145.7 MB. This is a delta (partial) update that requires 5.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c52bd8916181fde657d3f7b537f1999b4875c2e3.zip.