watchOS 5.3.6 (build 16U662) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2020-03-24T17:21:33Z. The update package is 59.81 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: e529f22cb505152dc1f39db1c89031b15aef3ed0.zip.