iPadOS 8.3 (build 12F69) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2015-04-08T17:56:08Z. The update package is 710.55 MB. This is a delta (partial) update that requires 8.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b642b1a1ef7707e8adc9a35221a3594fe6cf7c6d.zip.