iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone X (Global), released on 2019-01-22T18:08:49Z. The update package is 1.54 GB. This is a delta (partial) update that requires 11.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 62d5f7cf4b9d361b6a7731bb543dbe8723347516.zip.