watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2018-11-15T18:08:55Z. The update package is 570.36 MB. This is a delta (partial) update that requires 5.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b6a77049806688c74144a6bfeda50ac21812c25c.zip.