iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad mini 4 (Cellular), released on 2018-04-24T17:07:20Z. The update package is 1.26 GB. This is a delta (partial) update that requires 10.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a27871c1dfd2c573327fed56efd5780a42d3126f.zip.