iOS 9.3 (build 13E5214d) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2016-02-22T17:47:40Z. The update package is 111.87 MB. This is a delta (partial) update that requires 9.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 66bf674bf57f598da4c37c18afd7a815fc03d634.zip.