iOS 13.1 (build 17A5831c) is an official Apple over-the-air update for the iPhone X (GSM), released on 2019-09-04T17:06:15Z. The update package is 490.17 MB. This is a delta (partial) update that requires 13.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 27098a2d5fa3e5364cc1e2018e0f410b31b29b4c.zip.