watchOS 6.3.1 (build 17U224) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2026-02-02T18:44:17Z. The update package is 301.27 MB. This is a delta (partial) update that requires 6.2 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 25b698516df5c02bfac03532e6379964d095224d.zip.