With this approach I get the error “Uncaught (in promise) Error: Property “specialDates” does not exist in Element sap.ui.unified.Calendar#Screen2–ui_unified_Calendar1″, even though it is there (see screenshot). The same goes with “specialDatesPath2.
There is also the property “specialDatesPath”, but here I guess I have to provide an expression where to find the special dates in the data model.