iOS 10.3 (build 14E277) is an official Apple over-the-air update for the iPhone 6, released on 2017-03-27T16:58:09Z. The update package is 582.2 MB. This is a delta (partial) update that requires 10.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 0f5108564d87929f5664ddd8efe6f9a699ae56dc.zip.