watchOS 5.1.2 (build 16S46) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2018-12-06T18:03:57Z. The update package is 736.49 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3b4dbcd9039613f9ab3cf31923f9482e9c377584.zip.