I'm sorry, but I'm not sure I understand. 1. You have a working app that people like. 2. You have a set of new features that are being requested by some users

I'm sorry, but I'm not sure I understand. 1. You have a working app that people like. 2. You have a set of new features that are being requested by some users. Seems to me that the obvious solution is to bundle all of these new features, create a "premium account", and charge a monthly fee to those who wish to upgrade. Voila!