watchOS 5.3.2 (build 16U611) is an official Apple over-the-air update for the Apple Watch Series 1 (42mm), released on 2019-09-26T17:09:46Z. The update package is 823.46 MB. This is a delta (partial) update that requires 4.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 44e27b4fe3628c16179ae0538ed8b3bf39297422.zip.