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 531.39 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: 75092409b4eb74480c278cfd2bd35ae7cb9ecb5d.zip.