This property defines the revision sequence number of the calendar component within a sequence of revisions.
When a calendar component is created, its sequence number is 0. It is monotonically incremented by the "Organizer's" CUA each time the "Organizer" makes a significant revision to the calendar component.
The "Organizer" includes this property in an iCalendar object that it sends to an "Attendee" to specify the current version of the calendar component.
The "Attendee" includes this property in an iCalendar object that it sends to the "Organizer" to specify the version of the calendar component to which the "Attendee" is referring.
A change to the sequence number is not the mechanism that an "Organizer" uses to request a response from the "Attendees". The "RSVP" parameter on the "ATTENDEE" property is used by the "Organizer" to indicate that a response from the "Attendees" is requested.
Recurrence instances of a recurring component MAY have different sequence numbers.
This property is defined by the following notation:
seq = "SEQUENCE" seqparam ":" integer CRLF ; Default is "0"
seqparam = *(";" other-param)
The following is an example of this property for a calendar component that was just created by the "Organizer":
The following is an example of this property for a calendar component that has been revised two different times by the "Organizer":