Would like to have a quick advice. I'm currently have an Ipad 4 Wifi version with IOS 6.1. As more and more apps not able to run on IOS 6, I plan to upgrade it to IOS 8 and jailbreak it. What is the recommendation IOS 8 version for the Ipad 4 Wifi as I found some user complain IOS 8.4 causing lag performance on many devices. Thank you.