iPadOS 8.4.1 (build 12H321) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2015-08-13T18:05:08Z. The update package is 1.07 GB. This is a delta (partial) update that requires 7.1.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 610fb5e195c4eddfc7ba194200311dba65ffefce.zip.