iOS 9.3 (build 13E233) is an official Apple over-the-air update for the iPhone 4s, released on 2016-03-21T18:56:13Z. The update package is 197.28 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: ec323caa0ea7d03600c9d6e4508836496e15807e.zip.