watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2018-11-15T21:18:46Z. The update package is 55.96 MB. This is a delta (partial) update that requires 5.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9f6b9fb00fd9ea3060d058808aa167d4aa050613.zip.