watchOS 5.1.2 (build 16S5042a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-11-07T21:14:52Z. The update package is 168.05 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: e134bae927864d59038737df995aeac3b41ff8da.zip.