watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-11-15T18:08:34Z. The update package is 733.82 MB. This is a delta (partial) update that requires 4.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0753c5b2a60dd263a2353f3594954660ddc700ed.zip.