http://www.iphonehacks.com/2016/02/apple-stops-signing-ios-9-2-firmware.html
http://www.redmondpie.com/ios-9.1-firmware-is-no-longer-being-signed-by-apple/
http://www.redmondpie.com/ios-9.1-jailbreak-status-update/
https://www.reddit.com/r/jailbreak/comments/3xr6k8/news_apple_stops_signing_91/
https://www.freeflour.com/how-to-downgrade-ios-9-2-to-ios-9-1-ios-9-0-2-jailbreak/
http://www.iphonehacks.com/2015/10/5-things-jailbreakers-should-know-as-we-wait-for-ios-9-1-jailbreak.html