iOS 9.3 (build 13E5191d) is an official Apple over-the-air update for the iPhone 4s, released on 2016-01-25T20:52:41Z. The update package is 64.28 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: ad2103716bc4e84f93584868dd1f5e022d33f526.zip.