iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad mini 3 (China), released on 2018-04-24T17:06:59Z. The update package is 704.5 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8fed0cb03fd0b3c1cf18950ca8e545ab2cf3ad83.zip.