watchOS 5.1.2 (build 16S5042a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2018-11-07T21:15:26Z. The update package is 176.75 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: 6368b9370dd1a89cd35890e329f387c0ca4fb4d8.zip.