iOS 9.9.13.1 (build 17A844) is an official Apple over-the-air update for the iPhone XS Max (China), released on 2019-09-24T17:11:21Z. The update package is 3.25 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: fb92394b60526cfbf1a767fc913553089bcb733f.zip.