iPadOS 9.3 (build 13E233) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2016-03-21T18:55:44Z. The update package is 1 GB. This is a delta (partial) update that requires 8.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ad572d0f949ef3263193147394f912c981bb2622.zip.