This app implements many RPN flavors. They used to be sold as apps: Touch Fin, Touch Palladium, Touch Fin Black-Scholes, Touch 10i, Touch 11i, Touch 15i and Touch 16i.
Out of the box, the app offers two free flavors: financial and scientific. To change the active flavor, press ON to go to Settings, touch the option "Choose flavor" and select the desired flavor.
The flavors "Financial Premium" e "Scientific Premium" are functionally equal to the free flavors, except they are ad-free.
Ready-to-use flavors are shown without a price. Flavors available for purchase show a price in your currency. If you want to release a flavor, touch it and follow the Google Play instructions. Once the purchase is confirmed, the flavor is activated right away.
If you have purchased two or more RPN flavors, you can activate the fast swap buttons. They are shortcuts to exchange between e.g. financial and scientific flavors without having to open the Settings panel.
The fast swap shortcuts can be configured via the "Flavor fast swap buttons" panel of Settings. At most three flavors can be enabled to have shortcuts, and at most two shortcuts are shown on the main screen.
The fast swap buttons are completely disabled when any free flavor is in use.
The Black-Scholes flavor is "apocryphal" — there has never been a physical calculator with this layout. Read this instruction page to see how it works.