iOS 9.3 (build 13E237) is an official Apple over-the-air update for the iPhone 5c (GSM), released on 2016-03-28T16:52:38Z. The update package is 226.3 MB. This is a delta (partial) update that requires 9.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 96dca0bd61a0ea61e26d36ea0c3fa580ca7ffffb.zip.