watchOS 5.1.3 (build 16S6535) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-01-22T18:11:09Z. The update package is 83.25 MB. This is a delta (partial) update that requires 5.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: aa07180796fe56d660a85df8ec744213769c626e.zip.