iOS 8.4 (build 12H143) is an official Apple over-the-air update for the iPhone 6+, released on 2015-06-30T15:51:24Z. The update package is 222 MB. This is a delta (partial) update that requires 8.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8ef95e6b5f3bd9fd6aa5be558121796f59d512e3.zip.