watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2018-11-15T21:18:40Z. The update package is 144.03 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: 02552a255e03ba62c473bc1c7fd0659840442643.zip.