watchOS 6.3 (build 17U216) is an official Apple over-the-air update for the Apple Watch Series 5 (44mm, LTE), released on 2021-01-26T18:27:30Z. The update package is 459.42 MB. This is a delta (partial) update that requires 6.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: cf4b5e698e7dcdfd842f96b5b87dd0bd7bf58d6c.zip.