If you have already paid for the premium-features through an in-app-purchase from within the free version, you don't need to purchase this app. This app unlocks the same features as the in-app-purchase of the free version.
Purchasing this app unlocks the "premium" features of the free "DynamicNotifications" app. This isn't a standalone app, but a "key" that you need to install in addition to the free version, which can be found here: http://goo.gl/S1Glu5
Please open this app once after you've downloaded it, and keep it installed afterwards. You can hide it from your launcher using the "Hide from launcher" menu option after the unlock is complete.