watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 3 (42mm, LTE), released on 2026-02-02T18:44:22Z. The update package is 733.09 MB. This is a delta (partial) update that requires 6.0 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: df32666e631fc2cd454ef0818c4d6f4a4362ecb0.zip.