watchOS 5.3.5 (build 16U652) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm, LTE), released on 2020-02-18T18:07:01Z. The update package is 74.09 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: 603f3b77cc09003441d1b07796dd33d0308fe4db.zip.