iOS 13.3.1 (build 17D5050a) is an official Apple over-the-air update for the iPhone 11, released on 2020-01-22T18:07:25Z. The update package is 252.31 MB. This is a delta (partial) update that requires 13.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 36c1fbb51957bc96b5ec2b4cfde9a3eb56246ebc.zip.