watchOS 5.3.3 (build 16U620) is an official Apple over-the-air update for the Apple Watch Series 4 (44mm), released on 2019-10-29T17:09:36Z. The update package is 58.23 MB. This is a delta (partial) update that requires 5.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: abc03bac87fdcaf51dcba0e3dc1ab56863975ae0.zip.