Use this command to import to the specified calendar events and todos that have previously been exported to a file using the export command. You must specify the file’s MIME content type in the content-in parameter.
If you do not specify either the starting or ending date, or you pass in 0 as the value for dtstart and dtend, the command adds all events and todos in the file to the specified calendar. If you specify a starting and ending date, the command imports only events and todos in the file that fall within the time range. Specify starting and ending dates in UTC time, which is indicated by the Z at the end of the date-time string.
You must use this command with an HTTP POST message, unlike other commands that can be used with an HTTP GET message. You attach the file containing the exported events and todos to the POST message. This file must be in either iCalendar (.ics) or XML (.xml) format.