watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2026-02-02T18:44:15Z. The update package is 189.24 MB. This is a delta (partial) update that requires 6.3 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: fca3fbac3ff844624abf966512c1e1940507c3d2.zip.