iOS 12.1.3 (build 16D40) is an official Apple over-the-air update for the iPhone XS Max (China), released on 2019-01-22T18:15:04Z. The update package is 502.69 MB. This is a delta (partial) update that requires 12.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 375d46f1162585e78cbbc6372c384b1ab305fd70.zip.