iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad mini 2 (China), released on 2018-04-24T17:06:19Z. The update package is 583.56 MB. This is a delta (partial) update that requires 11.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 522fc02b7ccc8de7c424bfa8cec69fb3c196533a.zip.