What is the German Calendar 2017 application, how does it work?

According to the introduction of Agus Haryanto, German Calendar 2017 is a Productivity app on the Android platform. There is currently a 1.19 version released on Dec 18, 2017, you can see the details below.

German Calendar 2017 with holidays in 2017 - 2020
You can use this calendar as calendar on the wall with ability to see
- Change picture calendar and set this height.
- the beginning day of the week on Sunday or Monday
- create event or note with symbol love birthday task Ring
- notification event reminder when the time arrives
- showing Holidays 2017