Network Working Group M. Douglass
Internet-Draft RPI
Intended status: Standards Track October 19, 2012
Expires: April 22, 2013
Event Publishing Extensions to Icalendar
draft-douglass-calendar-extension-01
Abstract
This specification introduces a number of new iCalendar properties
which are of particular use for event publishers and in social
networking.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 22, 2013.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions Used in This Document . . . . . . . . . . . . 3
2. Typed References . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Piano Concert Performance . . . . . . . . . . . . . . . . 4
3.2. Itineraries . . . . . . . . . . . . . . . . . . . . . . . 4
4. New Property Parameters . . . . . . . . . . . . . . . . . . . 5
4.1. Hash . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Id . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3. Idref . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Loctype . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.5. Parttype . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.6. Restype . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.7. Order . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.8. Title . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. New Properties . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Participant . . . . . . . . . . . . . . . . . . . . . . . 9
5.2. Styled-Description . . . . . . . . . . . . . . . . . . . . 11
5.3. Structured-Location . . . . . . . . . . . . . . . . . . . 12
5.4. Structured-Resource . . . . . . . . . . . . . . . . . . . 14
6. Participant Types . . . . . . . . . . . . . . . . . . . . . . 15
7. Extended examples . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 16
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9.1. Property Registrations . . . . . . . . . . . . . . . . . . 16
9.2. Parameter Registrations . . . . . . . . . . . . . . . . . 17
9.3. Participant Type Registrations . . . . . . . . . . . . . . 17
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
11. Normative References . . . . . . . . . . . . . . . . . . . . . 18
Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . 19
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
The currently existing iCalendar standard [RFC5545] lacks useful
methods for referencing additional, external information relating to
calendar components.
This document defines a number of properties referencing external
information that can provide additional information about an
iCalendar component. The intent is that such information can be
automatically discovered and used by clients. Formats such as VCARD
are likely to be most useful.
In addition a new property is defined to support HTML descriptions.
1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
2. Typed References
The properties defined here can all reference external meta-data
which may be used by applications to provide enhanced value to users.
By providing type information as parameters, clients and servers are
able to discover interesting references and make use of them, perhaps
for indexing or the presentation of additional related information
for the user.
These properties are designed to handle common use cases in event
publication. It is generally important to provide information about
the organizers of such events. Sponsors wish to be referenced in a
prominent manner. In social calendaring it is often important to
identify the active participants in the event, for example a school
sports team, and the inactive participants, for example the parents.
The [RFC5545] LOCATION property provides only an unstructured single
text value for specifying the location where an event (or "TODO"
item) will occur. This is inadequate for use cases where structured
location information (e.g. address, region, country, postal code) is
required or preferred, and limits widespread adoption of iCalendar in
those settings.
Using STRUCTURED-LOCATION, information about a number of interesting
locations can be communicated, for example, parking, restaurants and
the venue. Servers and clients can retrieve the objects when storing
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the event and use them to index by geographic location.
When a calendar client receives a calendar component it can search
the set of supplied properties looking for those of particular
interest. The TYPE and FMTTYPE parameters, if supplied, can be used
to help the selection.
Having located such a property, e.g. STRUCTURED-LOCATION with
TYPE=PARKING, the client can use http GET on the supplied URL perhaps
with an ACCEPT header set to specify the desired format. The
targeted server SHOULD respond with a 406 if the resource is not
available in the desired format(s).
3. Use Cases
The main motivation for these properties has been event publication
but there are opportunities for use elsewhere. The following use
cases will describe some possible scenarios.
3.1. Piano Concert Performance
In putting together a concert there are many participants: piano
tuner, performer, stage hands etc. In addition there are sponsors
and various contacts to be provided. There will also be a number of
related locations. A number of events can be created, all of which
relate to the performance in different ways.
There may be an iTip meeting request for the piano tuner who will
arrive before the performance. Other members of staff may also
receive meeting requests.
An event can also be created for publication which will have a
PARTICIPANT reference to the pianist providing vcard information
about the performer. This event would also hold information about
parking, local subway stations and the venue itself. In addition,
there will be sponsorship information for sponsors of the event and
perhaps paid sponsorship properties essentially advertising local
establishments.
3.2. Itineraries
These properties also provide opportunities for the travel industry.
When booking a flight the SPONSOR property can be used to provide
references to businesses at the airports and to car hire businesses
at the destination.
The embedded location information can guide the traveller at the
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airport or to their final destination. The contact information can
provide detailed information about the booking agent, the airlines
and car hire companies and the hotel.
4. New Property Parameters
4.1. Hash
Parameter name: HASH
Purpose: To specify a hash of the value of another property.
Format Definition:
This parameter is defined by the following notation:
hashparam = "HASH" "=" DQUOTE text "/" text DQUOTE
Description: This parameter can be specified on properties that are
variants of another property and is used to detect changes in that
property to enable the values of all variants to be kept
synchronized. Each property that uses the "HASH" parameter MUST
define which other property the "HASH" is calculated from.
The text value should be the hash value (encoded as a hexadecimal
string) followed by a single "/", followed by a token describing
the algorithm used to calculate the hash value. Algorithm names
from the IANA Hash Function Textual Names registry [] MUST be
used.
Example:
STYLED-DESCRIPTION;HASH="699EAEE6CDB049F8B
E9E3329AAC2415A/SHA-1":Some Text
4.2. Id
Parameter name: ID
Purpose: To uniquely identify a property.
Format Definition:
This parameter is defined by the following notation:
idparam = "ID" "=" param-value
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Description: This parameter can be specified on any property. It is
used to uniquely identify the property so it can be related to
other properties that specify an "IDREF" parameter whose value
matches the "ID" value. Properties within the same component MUST
NOT have an "ID" parameter with the same value.
Example:
DESCRIPTION;ID=2:Some Text
STYLED-DESCRIPTION;ID=3;IDREF=2:Other Text
4.3. Idref
Parameter name: IDREF
Purpose: To relate one property to another.
Format Definition:
This parameter is defined by the following notation:
idrefparam = "IDREF" "=" param-value ; ??? multi-valued
Description: This parameter can be specified on any property. It is
used to uniquely relate one property to another. The value of the
"IDREF" parameter is set to the value of the "ID" parameter on the
property to which it is being related.
Example:
DESCRIPTION;ID=2:Some Text
STYLED-DESCRIPTION;IDREF=2:Other Text
4.4. Loctype
Parameter name: LOCTYPE
Purpose: To specify the type of location.
Format Definition:
This parameter is defined by the following notation:
loctypeparam = "LOCTYPE" "=" text
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Description: This parameter MAY be specified on STRUCTURED-LOCATION
and provides a way to differentiate multiple properties. For
example, it allows event producers to provide location information
for the venue and the parking.
Values for this parameter are taken from the values defined in
[RFC5545]. New location types SHOULD be registered in the manner
laid down in that specification
4.5. Parttype
Parameter name: PARTTYPE
Purpose: To specify the type of participant.
Format Definition:
This parameter is defined by the following notation:
parttypeparam = "PARTTYPE" "=" text
Description: This parameter MAY be specified on the PARTICIPANT
property, and defines the type of participation. Allowable values
are defined in Section 6.
4.6. Restype
Parameter name: RESTYPE
Purpose: To specify the type of resource.
Format Definition:
This parameter is defined by the following notation:
restypeparam = "RESTYPE" "=" text
Description: This parameter MAY be specified on STRUCTURED-RESOURCE
and provides a way to differentiate multiple properties.
Values for this parameter are taken from the values defined in
[todo]. New resource types SHOULD be registered in the manner
laid down in that specification
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4.7. Order
Parameter name: ORDER
Purpose: To define ordering for the associated property.
Format Definition:
This parameter is defined by the following notation:
orderparam = "ORDER" "=" (1*2DIGIT / "10")
; An integer between 1 and 100.
Description: The ORDER parameter is OPTIONAL and is used to indicate
the relative ordering of the corresponding instance of a property.
Its value MUST be an integer between 1 and 100 that quantifies the
order. Lower values correspond to a higher level of ordering,
with 1 being the highest.
When the parameter is absent, the default MUST be to interpret the
property instance as being at the lowest level of ordering.
Note that the value of this parameter is to be interpreted only in
relation to values assigned to other correcsponding instances of
the same property in the same entity. A given value, or the
absence of a value, MUST NOT be interpreted on its own.
This parameter MAY be applied to any property that allows multiple
instances.
4.8. Title
Parameter name: TITLE
Purpose: To provide a human readable title.
Format Definition:
This parameter is defined by the following notation:
titleparam = "TITLE" "=" text
Description: This parameter MAY be specified on all properties
defined in this specification, and provides a human readable
label, perhaps for icons or links..
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5. New Properties
5.1. Participant
Property name: PARTICIPANT
Purpose: This property provides a typed reference to external
information about participants in an event or optionally a plain
text typed value.
Value type: The default value type for this property is URI. The
value type can also be set to TEXT to indicate plain text content.
Property Parameters: Non-standard, title, parttype, order or format
type parameters can be specified on this property.
Conformance: This property MAY be specified in any iCalendar
component.
Description: When used in a component the value of this property
points to information about an event participant. This is NOT an
attendee in a scheduling sense and the ATTENDEE property may in
fact be specified in addition. Participants in events can be
individuals or organizations, for example a soccer team, the
spectators, or the musicians.
Format Definition:
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This property is defined by the following notation:
participant = "PARTICIPANT" partparam (":" uri) /
(
";" "VALUE" "=" "TEXT"
":" text
)
CRLF
partparam = *(
; the following are OPTIONAL
; but MUST NOT occur more than once
(";" fmttypeparam) /
(";" titleparam) /
(";" orderparam) /
(";" parttypeparam) /
; the following is OPTIONAL
; and MAY occur more than once
(";" other-param)
)
Note: When the ORDER parameter is supplied it defines the ordering
of PARTICIPANT properties with the same value for the TYPE
parameter.
Example:
The following is an example of this property. It points to a
VCARD providing information on an event participant.
PARTICIPANT;PARTTYPE=PRINCIPAL_PERFORMER:
http://dir.example.com/vcard/aviolinist.vcf
Example:
The following is an example referring to a VCARD providing
information on the primary contact.
PARTICIPANT;FMTTYPE=text/vcard;
PARTTYPE=PRIMARY-CONTACT;TITLE=A contact:
http://dir.example.com/vcard/contacts/contact1.vcf
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Example:
The following is an example of the property used to link to VCARD
information on the event planner.
PARTICIPANT;FMTTYPE=text/vcard;
PARTTYPE=PLANNER-CONTACT;TITLE=ClownsIsUs:
http://dir.example.com/vcard/clowns-is-us.vcf
5.2. Styled-Description
Property name: STYLED-DESCRIPTION
Purpose: This property provides a more complete description of the
calendar component than that provided by the "SUMMARY" property.
Value type: The default value type for this property is TEXT. The
value type can also be set to URI. Other text-based value types
can be used when defined in the future. Clients MUST ignore any
properties with value types they do not understand.
Property Parameters: IANA, non-standard, hash, id, idref, alternate
text representation, and language property parameters can be
specified on this property.
Conformance: The property can be specified multiple times in the
"VEVENT", "VTODO", "VJOURNAL", or "VALARM" calendar components.
Description: This property is used in the "VEVENT" and "VTODO" to
capture lengthy textual descriptions associated with the activity.
This property is used in the "VJOURNAL" calendar component to
capture one or more textual journal entries. This property is
used in the "VALARM" calendar component to capture the display
text for a DISPLAY category of alarm, and to capture the body text
for an EMAIL category of alarm.
VALUE=TEXT is used to provide html variants of the plain-text
DESCRIPTION property.
VALUE=URI is used to provide a link to html content which is
expected to be displayed inline as part of the event.
The "HASH" parameter value is calculated from the value of any
"DESCRIPTION" property present in the same component. If no
"DESCRIPTION" is present, then the "HASH" parameter MUST NOT be
present.
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The intent of this property is limited to providing a styled
version of the DESCRIPTION property. The URL property should be
used to link to websites or other related information.
Format Definition:
This property is defined by the following notation:
styleddescription = "STYLED-DESCRIPTION" styleddescparam ":"
text CRLF
styleddescparam = *(
;
; The following are OPTIONAL,
; but MUST NOT occur more than once.
;
(";" altrepparam) / (";" languageparam) /
(";" hashparam) / (";" idparam) / (";" idrefparam) /
;
; The following is OPTIONAL,
; and MAY occur more than once.
;
(";" valueparam)
; The value of this parameter MUST match the type of
; data supplied in the value of the property
Example:
The following is an example of this property. It points to a
venue.
STRUCTURED-LOCATION;TITLE="The venue":
http://dir.example.com/venues/big-hall.vcf
5.3. Structured-Location
Property name: STRUCTURED-LOCATION
Purpose: This property provides a typed reference to external
information about the location of an event or optionally a plain
text typed value.
Value type: The default value type for this property is URI. The
value type can also be set to TEXT to indicate plain text content.
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Property Parameters: IANA, non-standard, title, loctype or format
type parameters can be specified on this property.
Conformance: This property MAY be specified zero or more times in
any iCalendar component.
Description: When used in a component the value of this property
provides information about the event venue or of related services
such as parking, dining, stations etc..
Format Definition:
This property is defined by the following notation:
strucloc = "STRUCTURED-LOCATION" struclocparam (":" uri) /
(
";" "VALUE" "=" "TEXT"
":" text
)
CRLF
struclocparam = *(
; the following are OPTIONAL
; but MUST NOT occur more than once
(";" fmttypeparam) /
(";" titleparam) /
(";" loctypeparam) /
; the following is OPTIONAL
; and MAY occur more than once
(";" other-param)
)
Example:
The following is an example of this property. It points to a
venue.
STRUCTURED-LOCATION;TITLE="The venue":
http://dir.example.com/venues/big-hall.vcf
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5.4. Structured-Resource
Property name: STRUCTURED-RESOURCE
Purpose: This property provides a typed reference to external
information about a resource or optionally a plain text typed
value.
Value type: The default value type for this property is URI. The
value type can also be set to TEXT to indicate plain text content.
Property Parameters: IANA, non-standard, title, restype or format
type parameters can be specified on this property.
Conformance: This property MAY be specified zero or more times in
any iCalendar component.
Description: When used in a component the value of this property
provides information about resources used for the event.
Format Definition:
This property is defined by the following notation:
strucres = "STRUCTURED-LOCATION" strucresparam (":" uri) /
(
";" "VALUE" "=" "TEXT"
":" text
)
CRLF
strucresparam = *(
; the following are OPTIONAL
; but MUST NOT occur more than once
(";" fmttypeparam) /
(";" titleparam) /
(";" restypeparam) /
; the following is OPTIONAL
; and MAY occur more than once
(";" other-param)
)
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Example:
The following is an example of this property. It refers to a
projector.
STRUCTURED-RESOURCE;restype="projector":
http://dir.example.com/projectors/3d.vcf
6. Participant Types
This section describes types of participation and provide registered
values for the PARTICPANT property TYPE parameter.
ACTIVE: A participant taking an active role - for example a team
member.
INACTIVE: A particpant taking an inactive part - for example an
audience member.
SPONSOR: A sponsor of the event. The ORDER parameter may be used
with this participant type to define the relative order of
multiple sponsors.
CONTACT: Contact information for the event. The ORDER parameter may
be used with this participant type to define the relative order of
multiple contacts.
BOOKING-CONTACT: Contact information for reservations or payment
EMERGENCY-CONTACT: Contact in case of emergency
PUBLICITY-CONTACT: Contact for publicity
PLANNER-CONTACT: Contact for the event planner or organizer
PERFORMER: A performer - for example the soloist or the
accompianist. The ORDER parameter may be used with this
participant type to define the relative order of multiple
sponsors. For example,ORDER=1 could define the principal
performer or soloist.
SPEAKER: Speaker at an event
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7. Extended examples
The following are some examples of the use of the properties defined
in this specification. They include additional properties defined in
[I-D.daboo-icalendar-extensions] which includes IMAGE and LIVEFEED.
7.1. Example 1
The following is an example of a VEVENT describing a concert. It
includes location information for the venue itself as well as
references to parking and restaurants.
BEGIN:VEVENT
CREATED:20101116T145739Z
DESCRIPTION: Piano Sonata No 3\n
Piano Sonata No 30
DTSTAMP:20101116T145739Z
DTSTART;TZID=America/New_York:20110315T150000Z
DTEND;TZID=America/New_York:20110315T163000Z
LAST-MODIFIED:20101116T145739Z
SUMMARY:Beethoven Piano Sonatas
UID:123456
STRUCTURED-LOCATION;TITLE="The venue":
http://dir.example.com/venues/big-hall.vcf
STRUCTURED-LOCATION;TITLE="The venue":
http://dir.example.com/venues/parking.vcf
PARTICIPANT;PARTTYPE=SPONSOR:http://example.com/sponsor.vcf
PARTICIPANT;PARTTYPE=PERFORMER:
http://www.example.com/people/johndoe.vcf
END:VEVENT
8. Security Considerations
Applications using these property need to be aware of the risks
entailed in using the URIs provided as values. See [RFC3986] for a
discussion of the security considerations relating to URIs.
9. IANA Considerations
9.1. Property Registrations
This document defines the following new iCalendar properties to be
added to the registry defined in Section 8.2.3 of [RFC5545]:
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+---------------------+---------+----------------------+
| Property | Status | Reference |
+---------------------+---------+----------------------+
| PARTICIPANT | Current | RFCXXXX, Section 5.1 |
| STYLED-DESCRIPTION | Current | RFCXXXX, Section 5.2 |
| STRUCTURED-LOCATION | Current | RFCXXXX, Section 5.3 |
| STRUCTURED-RESOURCE | Current | RFCXXXX, Section 5.4 |
+---------------------+---------+----------------------+
9.2. Parameter Registrations
This document defines the following new iCalendar property parameters
to be added to the registry defined in Section 8.2.4 of [RFC5545]:
+--------------------+---------+----------------------+
| Property Parameter | Status | Reference |
+--------------------+---------+----------------------+
| HASH | Current | RFCXXXX, Section 4.1 |
| ID | Current | RFCXXXX, Section 4.2 |
| IDREF | Current | RFCXXXX, Section 4.3 |
| LOCTYPE | Current | RFCXXXX, Section 4.4 |
| PARTTYPE | Current | RFCXXXX, Section 4.5 |
| RESTYPE | Current | RFCXXXX, Section 4.6 |
| ORDER | Current | RFCXXXX, Section 4.7 |
| TITLE | Current | RFCXXXX, Section 4.8 |
+--------------------+---------+----------------------+
9.3. Participant Type Registrations
The following table has been used to initialize the participant types
registry.
+-------------------+---------+--------------------+
| Participant Type | Status | Reference |
+-------------------+---------+--------------------+
| ACTIVE | Current | RFCXXXX, Section 6 |
| INACTIVE | Current | RFCXXXX, Section 6 |
| SPONSOR | Current | RFCXXXX, Section 6 |
| CONTACT | Current | RFCXXXX, Section 6 |
| BOOKING-CONTACT | Current | RFCXXXX, Section 6 |
| EMERGENCY-CONTACT | Current | RFCXXXX, Section 6 |
| PUBLICITY-CONTACT | Current | RFCXXXX, Section 6 |
| PLANNER-CONTACT | Current | RFCXXXX, Section 6 |
| PERFORMER | Current | RFCXXXX, Section 6 |
| SPEAKER | Current | RFCXXXX, Section 6 |
+-------------------+---------+--------------------+
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10. Acknowledgements
The author would like to thank Chuck Norris of eventful.com for his
work which led to the development of this RFC.
The author would also like to thank the members of the Calendaring
and Scheduling Consortium Event Publication technical committee and
the following individuals for contributing their ideas and support:
Cyrus Daboo, John Haug, Dan Mendell, Scott Otis,
The authors would also like to thank the Calendaring and Scheduling
Consortium for advice with this specification.
11. Normative References
[I-D.daboo-icalendar-extensions]
Daboo, C., "New Properties for iCalendar",
draft-daboo-icalendar-extensions-05 (work in progress),
June 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types
Registry", RFC 4589, July 2006.
[RFC5545] Desruisseaux, B., "Internet Calendaring and Scheduling
Core Object Specification (iCalendar)", RFC 5545,
September 2009.
[W3C.REC-xml-20060816]
Yergeau, F., Paoli, J., Maler, E., Sperberg-McQueen, C.,
and T. Bray, "Extensible Markup Language (XML) 1.0 (Fourth
Edition)", World Wide Web Consortium FirstEdition REC-xml-
20060816, August 2006,
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<http://www.w3.org/TR/2006/REC-xml-20060816>.
Appendix A. Change log
v01 2012-10-18 MD Many changes.
o SPONSOR and STRUCTURED-CONTACT are now in PARTICIPANT
o Add a STRUCTURED-RESOURCE property
o STYLED-DESCRIPTION to handle rich text
o Much more...
2011-01-07
o Remove MEDIA - it's going in the Cyrus RFC
o Rename EXTENDED-... to STRUCTURED-...
o Add TYPE parameter to SPONSOR
v00 2007-10-19 MD Initial version
Author's Address
Michael Douglass
Rensselaer Polytechnic Institute
110 8th Street
Troy, NY 12180
USA
Email: douglm@rpi.edu
URI: http://www.rpi.edu/
Douglass Expires April 22, 2013 [Page 19]