watchOS 6.3 (build 17U216) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2021-01-26T18:26:30Z. The update package is 86.79 MB. This is a delta (partial) update that requires 6.2.8 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: bbe83d9696006505d2e020b93578264107b822b6.zip.