In the next update, the calculator will mostly function the same as before. However, there are some layout changes. For consistency, all versions of android will now have an action bar (the navigation bar at the top of the screen). I am considering making it optional for devices with a menu button. Here is a screenshot of the new UI I have created. Things are set in stone yet, so there could be some changes before the actual update.
The default keyboard color scheme is shown above. With this, only the digit and the four basic operator keys are colored (digits are white and operators are blue). Everything else is a dark gray. However, users will have the options to change to three other color schemes: light, medium, and dark. In these three schemes, similar keys will be colored the same. Here are three screenshots showing light, medium, and dark.
In the paid version users will be able to set any key to any choice of color they want when creating their custom keyboards.
There will also be some changes to the graph screen. Currently when graphing you have to hit an up arrow to open up a tabbed view to view reading, bounds, and equations. The up arrow will be going away in the new UI. Instead, there will be a drop down selection in the action bar to select which tab you want to view (and a None selection to view the graph full screen). In the image below, you can see that "Readings" is selected in the action bar so the readings tab is shown.
Finally, when graphing in landscape the screen will be split vertically instead of the current horizontal split. This should make it must easier to use graphing in landscape.