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 962.73 MB. This is a delta (partial) update that requires 7.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 735d7b0b5b052a2c91e404298a39e5a3cbe72bec.zip.