watchOS 5.3.6 (build 16U662) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2020-03-24T17:21:22Z. The update package is 65.09 MB. This is a delta (partial) update that requires 5.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 51dea26451855e9899c0a749676bfcc07c86bceb.zip.