By default, the verse calendar in Android App has no reminder set (for example, 15 minutes before). That is fatal. If someone forgets to select, then you get no reminder for the appointment. You can not configure that in the app settings. For this I opened a PMR 68896,011,724. The 1st Level lady did not give me any good prospects for implementation. Only if there are enough other customers who report the same, that would possibly be implemented (!).
There already exists an Enhancement Request, but I get no feedback if the ER is in progress or anything. Furthermore I cannot access the blog app :-(