You can access Registration Form in the app to make payment via Paypal and you will receive the regisatrion code to upgrade to Pro verion
Note: The regisatrion code can be use on many devices

Quoting Weilly:

My Friend recommened me to use this app
How do I change the background color in each widget?

Dear you
To change the background color in widgets, you open the Properties windows and access Color item to change colors for items.

Quoting CCathery:

I have installed it. It can sync with my mobile app.
How can it sync with Gg cal?

CalendarDC can sync with GG Calendar. You can open Property Dialog and access Synchronization item to add your GG account you want to sync.

Quoting ToniP:

It is good app. I use it to replace GG cal. How can i resize widgets and color text on widgets?

Dear you
To change the size in each widget, you can perform right click on the widget and choose Change size menu to change size of the widget.