watchOS 5.1.2 (build 16S46) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-12-06T18:04:10Z. The update package is 136.78 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: 94a39a15e0aa818dff18e5177ceb6bd5e21b656b.zip.