iOS 8.4 (build 12H143) is an official Apple over-the-air update for the iPhone 5c (GSM), released on 2015-06-30T15:51:20Z. The update package is 425.05 MB. This is a delta (partial) update that requires 8.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e6b2ef2f944173eadb0d371b79a2e7cc5a4fbf27.zip.