I really like this app, and will keep using it regardless of whether my suggestions create a change to the software, but I'd like to suggest that the keyboard could be equipped with a "minimize button." This would serve the purpose of not showing the typing keys, and leaving a few buttons at the bottom, in this minimized state. The buttons could expand the keyboard again, switch keyboards, hit the "Wifi" button", and backspace.
Otherwise, I completely endorse the application. The online interface isn't buggy, which I almost expected from the "instant" interface at first. This app is pretty well made. I would really appreciate if you made my changes, as I am one of few paying customers, it seems.
This application works very well on my 5th generation iPod touch, under iOS 9.2.1.