iOS 8.4 (build 12H4086d) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2015-04-27T17:47:06Z. The update package is 147.47 MB. This is a delta (partial) update that requires 8.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ffb1faa981aecbe2620090d0633702d187c1e57d.zip.