iOS 8.3 (build 12F70) is an official Apple over-the-air update for the iPhone 6+, released on 2015-04-08T17:56:16Z. The update package is 1.75 GB. This is a delta (partial) update that requires null already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8327d000cc7fe6aaa7275212bddb565cc2f2386a.zip.