iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad 5 (Cellular), released on 2018-04-24T17:08:12Z. The update package is 100.83 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4495e9ce781843ed90c6c98b6726edd8e8cea994.zip.