watchOS 5.1.3 (build 16S535) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-01-22T18:11:03Z. The update package is 736.84 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: e5d3b7c5f2b8483899c34092b0a28db956816756.zip.