iOS 13.3.1 (build 17D5044a) is an official Apple over-the-air update for the iPhone X (GSM), released on 2020-01-14T18:21:03Z. The update package is 186.74 MB. This is a delta (partial) update that requires 13.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7028d36325adc29ea6670531928607cd80113be0.zip.