An updated internet-draft is available from the IETF.
Abstract: «This is the second release of a iCalendar. After having learned from RFC-2445. This document represents the common objects needed for basic calendaring. The VTODO, VJOURNAL, VTIMEZONE, recurrence rules (RDATE remains), and scheduling and their associated properties have been removed. These removals are expected to appear in new memos at a later time and will be independent extensions of this specification. The new EXTENSIONS property will exist to allow for compatible sets of extensions.»