watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2019-10-29T17:09:30Z. The update package is 73.79 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: bf177f22a7818ef56a1d70ac02960fdc6c3a0fbe.zip.