watchOS 5.3.5 (build 16U652) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2020-02-18T18:07:03Z. The update package is 74.12 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: 75d4d0deb6c23dd2c122e96f5d4997d71d493f66.zip.