iOS 8.3 (build 12F5070) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2015-04-08T17:56:03Z. The update package is 1.33 GB. This is a delta (partial) update that requires 8.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8d1abca08907b421e0c236907b7c75604c6c3e2c.zip.