How to upgrade to premium version? – Marvin 3 Review

I looked at few ePub readers and Marvin 3 is my personal favorite. The interface is clean and customizable. After I tried the full screen and I am ready to upgrade to premium version. To my surprise I cannot find the option for in-app purchase. I guess I have to wait for the 1 day trial to pass before I can upgrade. Keep up the good work. I love to support awesome application like this one.
Review by S.T. Boston on Marvin 3.