watchOS 5.1.2 (build 16S46) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2018-12-06T18:04:51Z. The update package is 148.83 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: 866d9f35e4de0af65e696622f9675092daa229eb.zip.