iPadOS 9.3.1 (build 13E238) is an official Apple over-the-air update for the iPad 4 (GSM), released on 2016-03-31T16:52:26Z. The update package is 362.04 MB. This is a delta (partial) update that requires 9.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 91d129c28cab6f8c5ae4bc16161203c217efd0fe.zip.