watchOS 6.3 (build 17U216) is an official Apple over-the-air update for the Apple Watch Series 3 (38mm), released on 2021-01-26T18:26:34Z. The update package is 468.95 MB. This is a delta (partial) update that requires 6.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ea62e17bdd6b954dd3527bf4ee44b4037b552e80.zip.