iOS 13.3.1 (build 17D5050a) is an official Apple over-the-air update for the iPhone 11 Pro Max, released on 2020-01-22T18:07:27Z. The update package is 129.78 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: cced9145745b08400072ab12eef2e8efee96afb6.zip.