iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad mini 4 (Cellular), released on 2018-04-24T17:07:21Z. The update package is 1.23 GB. This is a delta (partial) update that requires 10.3.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 23b35ed18d1f7e830b7225b5bafc71fe0a7132f8.zip.