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The iCalendar [RFC5545] data format is used to represent calendar data and is used with the iCalendar Transport-Independent Interoperability Protocol (iTIP) [RFC5546] to handle scheduling operations between calendar users. iCalendar is in widespread use, and in accordance with provisions in that specification, extension elements have been added by various vendors to the data format in order to support and enhance capabilities. This specification collects a number of these ad hoc extensions and uses the new IANA registry capability defined in [RFC5545] to register standard variants with clearly defined definitions and semantics. In addition, some new elements are introduced for features that vendors have recently been requesting.

This document was automatically converted to XHTML using an RFC to HTML converter with the original text document at the Internet Engineering Task Force web site at .  The original text document should be referred to if there are any errors or discrepancies found in this document.

Need to test your iCalendar feeds?

The iCalendar Validator provides developers and testers a method to validate their iCalendar feeds, which can take data from either a URL, file or text snippet and compare it against the RFC 5545 specification.  We believe we have one of the best iCalendar validation tools available on the internet. More information about the validator can be found here.