watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2019-10-29T17:09:31Z. The update package is 69.74 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: f408cee2d3e363f6fc73232be1d249237480013e.zip.