New features were added in iOS 8, now you can download third party software for keyboard and change your default keyboard. Apple is trying to look a little more like Android, and give to the developers more space for customization. From now swiftkey is available for iOS8, here is a small guide how you can change your keyboard in iOS 8 with Swiftkey.
Follow these steps:
Open App Store from iPhone and search for “iOS 8 Keyboard“, and from the list install “SwiftKey“.
Now open your phone settings, go to General Tab and select Keyboard.
From here, select Add new keyboard, from the list select Swiftkey and allow full access to Switfkey.
Open Messages app, tap on the “world icon” on keyboard and choose Swiftkey.
Now Swiftkey will be your default keybord. Enjoy!