watchOS 6.3 (build 17U208) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2020-12-14T18:08:55Z. The update package is 58.67 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: abc073a3ea0c67d6b8c395b5322b8e75a961c9d4.zip.