The api property (number) determines the event handling API version to be used.
DayPilot.Calendar.api1 - legacy API version (default in ASP.NET WebForms, ASP.NET MVC)
2 - current API version (default)
Event calendar/scheduling AJAX components. Available for JavaScript/HTML5/jQuery, ASP.NET, ASP.NET MVC. Build resource booking, project management, time tracking applications, personal and shared event calendars.
DayPilot