ICalendar is used and supported by many products, including Google Calendar, Apple Calendar (formerly iCal), IBM Notes (formerly Lotus Notes), Yahoo! Calendar, Evolution (software), eM Client, Lightning extension for Mozilla Thunderbird and SeaMonkey, and partially by Microsoft Outlook and Novell GroupWise. The file format is specified in a proposed Internet standard (RFC 5545) for calendar data exchange. With supporting software, such as an email reader or calendar application, recipients of an iCalendar data file can respond to the sender easily or counter-propose another meeting date/time. Files formatted according to the specification usually have an extension of. The Internet Calendaring and Scheduling Core Object Specification ( iCalendar) is a media type which allows users to store and exchange calendaring and scheduling information such as events, to-dos, journal entries, and free/busy information. ICalendar components and their properties
