iPadOS 8.4 (build 12H4125a) is an official Apple over-the-air update for the iPad Air 2 (WiFi), released on 2015-06-09T17:53:04Z. The update package is 142.54 MB. This is a delta (partial) update that requires 8.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4e3002b5e6b772942f019f5bf5d7a81324558587.zip.