watchOS 5.3.1 (build 16U600) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2019-08-26T17:14:10Z. The update package is 832.88 MB. This is a delta (partial) update that requires 4.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9270457ba059463663147b03cb9d08ac16a2dc8c.zip.