iPadOS 8.4.1 (build 12H321) is an official Apple over-the-air update for the iPad 3 (WiFi), released on 2015-08-13T18:05:08Z. The update package is 641.9 MB. This is a delta (partial) update that requires 8.0.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 87eb23fff495468b19529a9cfb2463afd6a1a4d1.zip.