iOS 12.1.3 (build 16D40) is an official Apple over-the-air update for the iPhone XS Max, released on 2019-01-22T18:15:08Z. The update package is 319.51 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: d02b369c8d39c669f547d2d5c4f3f4adbe1e5ff0.zip.