watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 4 (40mm, LTE), released on 2019-10-29T17:09:39Z. The update package is 56.2 MB. This is a delta (partial) update that requires 5.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6ef78125ef49bd55bcee12fa11f7167e24214d7c.zip.