iOS 12.1 (build 16B5089b) is an official Apple over-the-air update for the iPhone XS Max, released on 2018-10-22T17:01:59Z. The update package is 233.93 MB. This is a delta (partial) update that requires 12.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 82870682538ed2b8d42651ddb565137898ec863e.zip.