watchOS 5.3.10 (build 16U711) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2026-03-24T18:34:07Z. The update package is 54.32 MB. This is a delta (partial) update that requires 5.3.9 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 2440112a9dd160a3fb4ba2e954b2ebbf518a115c.zip.