iOS 8.1 (build 12B411) is an official Apple over-the-air update for the iPhone 4s, released on 2014-10-20T17:59:07Z. The update package is 962.82 MB. This is a delta (partial) update that requires 7.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 73572578239a28ac003431225a3d595416eebe88.zip.