watchOS 5.3.1 (build 16U600) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-08-26T17:14:21Z. The update package is 137.29 MB. This is a delta (partial) update that requires 5.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b690262fe32a9da9933a98b67f25d4af7d577687.zip.