watchOS 5.1.2 (build 16S5046a) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-11-15T18:08:35Z. The update package is 733.79 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9194e449d8d6d850bcc0f1c7a4f6861c94eecea4.zip.