iOS 9.0 (build 13A344) is an official Apple over-the-air update for the iPhone 4s, released on 2015-09-16T18:02:13Z. The update package is 895.56 MB. This is a delta (partial) update that requires 8.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3a9d10fbe9730878825f82e07c526c95935b0b92.zip.