watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2018-11-15T18:08:49Z. The update package is 408.76 MB. This is a delta (partial) update that requires 5.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f4395cd5dbb865f247089a00c44f2ea5fa9ee7dc.zip.