iPadOS 8.4 (build 12H143) is an official Apple over-the-air update for the iPad 3 (WiFi), released on 2015-06-30T15:51:09Z. The update package is 1.05 GB. 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: 5556bb400289c6c49c42c96e9236ef5a561d200c.zip.