iPadOS 8.1.3 (build 12B466) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2015-01-27T17:55:04Z. The update package is 985.48 MB. This is a delta (partial) update that requires 7.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 678db32b409fd1b709ae40ae2a0d831dce115371.zip.