watchOS 5.3.9 (build 16U693) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2020-11-05T18:19:56Z. The update package is 56.83 MB. This is a delta (partial) update that requires 5.3.5 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 5ea35c194a9997d1051bf46f71f19a481a1bd324.zip.