iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad 2 (Mid 2012), released on 2015-10-21T17:15:49Z. The update package is 804.53 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: 12b6a83a1eb3c4239cd69bcd958ed76e42dd5f47.zip.