iPadOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPad mini 3 (Cellular), released on 2016-03-31T16:53:45Z. The update package is 288.2 MB. This is a delta (partial) update that requires 9.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 85b2270c3870a69af7103d3410fb1d744ce707dc.zip.