As of the end of July, 2016 it is impossible to purchase a license for Spell Catcher X. The Kagi Store closed down.
Is Rainmaker Research going to continue making Spell Catcher X available and purchasable into the future? I note that I have it working near perfectly on 10.12.6beta. SCX continues to be a terrific and treasured application on macOS. I hope new discoverers and updaters can continue to obtain and use it on into the future.