iPadOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2016-03-31T16:54:17Z. The update package is 1.11 GB. This is a delta (partial) update that requires 8.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4b3a3e29d2c17d53b900b28c0e4a7cf5fc3243fa.zip.