watchOS 5.3.8 (build 16U680) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2020-07-15T17:28:20Z. The update package is 64.61 MB. This is a delta (partial) update that requires 5.3.5 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8365aa4acc3afc9dfae11069f3303e24673dc35e.zip.