iPadOS 8.4 (build 12H143) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2015-06-30T15:51:16Z. The update package is 432.94 MB. This is a delta (partial) update that requires 8.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: fbafb4cbefdd201e1e37399c6a504f619cec5058.zip.