iOS 8.4 (build 12H143) is an official Apple over-the-air update for the iPhone 4s, released on 2015-06-30T15:51:18Z. The update package is 299.46 MB. This is a delta (partial) update that requires 8.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6af4b13175b73383aaab55d40a1184a941e97f15.zip.