watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2019-10-29T17:09:40Z. The update package is 62.59 MB. This is a delta (partial) update that requires 5.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1287e03dea478cb4b8dd6a683e4fd82ba0ea22e8.zip.