iOS 8 has already being tested by developer and Apple is going to release to everyone in probably mid-september 2014. Of course iPhone 6 is going to be introduced. What really interests us is this, will be able to jailbreak iOS 8?
Like after all other big iOS updates, the current tools that help us to jailbreak iOS are probably not going to work to jailbreak iOS 8. That is because it is a completely new version, and hackers still don't know how it works to find a way to crack.
This does not mean it will never be able to be jailbroken, but we might need to wait for a little while to be able to jailbreak iOS 8.
iOS 8 is going to be compatible with iPhone 4s, iPhone 5, iPhone 5c, iPhone 5s. iPad 2, iPad 3rd generation, iPad 4th generation, iPad Air, iPad mini, iPad mini with Retina display and iPod touch 5th generation.
Another important things is this, if your device is already jailbroken and you update the current iOS version to any other iOS version such as iOS 8, anything related to jailbreak will be removed automatically so you will need to jailbreak again!
So if your target device is already jailbroken and the keylogger is working fine, do not upgrade the iOS version to iOS 8 until there is a tool to jailbreak iOS 8. Otherwise the keylogger will be deleted and you will not be getting activities from the target device!