iOS 8.3 (build 12F70) is an official Apple over-the-air update for the iPhone 5 (GSM), released on 2015-04-08T17:56:10Z. The update package is 904.4 MB. This is a delta (partial) update that requires 7.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5c9a9943787308a527ad616cf71031edb8829f19.zip.