iOS 9.3 (build 13E233) is an official Apple over-the-air update for the iPhone 4s, released on 2016-03-21T18:56:11Z. The update package is 932.59 MB. This is a delta (partial) update that requires 8.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e65a58d4dd7e4fe449240b7b7a0c3f7cb383f80f.zip.