watchOS 6.3 (build 17U216) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm, LTE), released on 2021-01-26T18:27:12Z. The update package is 458.53 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: 807bed26d1d21f586d04a67f812f8e49697eeba1.zip.