iPadOS 9.1 (build 13B137) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2015-10-12T16:56:49Z. The update package is 1.17 GB. This is a delta (partial) update that requires 9.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9d8e4a441c8becf9f71c87feab1a4f748ed63b7d.zip.