I have an application that produces an iCalendar feed (RFC 5545). The calendar feed works on Google Calendar and on Android but I have been getting reports that it isn't working on OS X Calendar (aka iCal). The calendar feed currently uses the RDATE element extensively and validates.
Does iCal support the RDATE element?
I have managed to get recurrence working on Apple devices by using RRULE with EXDATEs. The problem is this does not work properly on Android devices. (Argghhh!)