watchOS 5.1.2 (build 16S46) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-12-06T18:04:12Z. The update package is 978.3 MB. This is a delta (partial) update that requires 3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1d6f89e9838c5c60b4d0678082f3364d3ed45fae.zip.