watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2019-10-29T17:09:32Z. The update package is 64.96 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: 497dd9c8b04d66dca4b1ccc934d3cb719cf35615.zip.