iOS 8.4 (build 12H4086d) is an official Apple over-the-air update for the iPhone 6+, released on 2015-04-27T17:47:06Z. The update package is 169.32 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: 87945675d4e2360256cb054faae91d1936e584f1.zip.