watchOS 5.3.9 (build 16U693) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2020-11-05T18:19:35Z. The update package is 61.93 MB. This is a delta (partial) update that requires 5.3.6 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: c83ed95cfe2cdc7acc0908e57b4908c7a428256f.zip.