"Full timezone support via dynamic server calls rather than embedding timezone information in events - no more having event times wrong when timezones change and your software isn’t updated"

Traditionally calendar entries coded in iCalendar have had to include timezone information to allow interpretation of the date and time of an event, and can be incorrect if the timezones have changed since the information was put in the event. Having a separate, online timezone service which can be queried at any time will allow timezone information to be included by reference in events, rather than embedded in them, and ensure correct interpretation of dates and times even if the information changes.

Details: TC TIMEZONE.