iPadOS 8.4.1 (build 12H321) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2015-08-13T18:05:10Z. The update package is 424.57 MB. This is a delta (partial) update that requires 8.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a90409d394930fe703b60aba2bbadbce3aeeecbe.zip.