As a standard, iCalendar was first defined as RFC 2445 in 1998 by the Internet Engineering Task Force (IETF), an Internet Society (ISOC) activity. ISOC, as a non-profit organization, was created in 1992 to serve as lead on Internet-related standards, education, and policy.
2. The iCalendar standard was refined in 2009, becoming RFC 5545, then it was edited by Bernard Desruisseaux of Oracle Corporation.
3. RFC 5545 is now considered the iCalendar standard and supersedes the previous RFC. RFC 7986 was published in 2016.