iOS 12.3 (build 16F5155a) is an official Apple over-the-air update for the iPhone XS, released on 2019-05-07T17:04:16Z. The update package is 491.14 MB. This is a delta (partial) update that requires 12.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 136678ab4ceaecdc130eb1d632204a8880711986.zip.