iOS 12.1.3 (build 16D5032a) is an official Apple over-the-air update for the iPhone XS, released on 2018-12-19T18:06:58Z. The update package is 289.33 MB. This is a delta (partial) update that requires 12.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1f8c95059c62640ec30261ce270c758e4496a7f9.zip.