As you can imagine a lot of work was done in creating and developing smartChord. And it will need much more effort to improve and expand it. Buying the s.mart PLUS UNLIMITED version is the best way to say thanks to the developers, to provide the basis for future development and to do something good to yourself. The PLUS UNLIMITED has got about 25 more instruments and it includes all future chargeable functions and s.mart apps for a lifetime.