watchOS 5.3.10 (build 16U711) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2026-03-24T18:33:50Z. The update package is 462.47 MB. This is a delta (partial) update that requires 5.1.2 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 61e778a8a30880b9f3403cc53484e83a6d6ceba2.zip.