watchOS 5.3.9 (build 16U693) is an official Apple over-the-air update for the Apple Watch Series 2 (42mm), released on 2020-12-14T18:08:33Z. The update package is 467.95 MB. This is a delta (partial) update that requires 5.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: bc3b6677bd09c96d35781f34d5717f03cd3e8df8.zip.