iOS 12.1.3 (build 16D5032a) is an official Apple over-the-air update for the iPhone XS Max, released on 2018-12-19T18:06:59Z. The update package is 327.37 MB. This is a delta (partial) update that requires 12.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 05b91e82de62ca68973dff83c370a61aa0580621.zip.