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 742.12 MB. 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: 5ac7ef824378947b6edaf4e3051e0c406f80686c.zip.