watchOS 5.3.1 (build 16U600) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-08-26T17:14:08Z. The update package is 991.94 MB. This is a delta (partial) update that requires 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: c4cb3ae5f662b55c1c86dbf5e078447f2ad61423.zip.