watchOS 6.3 (build 17U216) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2021-01-26T18:26:29Z. The update package is 170.71 MB. This is a delta (partial) update that requires 6.2.6 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0e5c25f03becec62572e61165f0a01d2c9be1bdf.zip.