title: Update Existing Outlook Calendar Appointment
body: <p>I am implementing an application that manages meetings. As one of the feature, it can send a meeting request to Outlook.</p>
  
  <p>The problem is, that when the meeting is updated, the message sent, does not update Outlook calendar. I am using MS Outlook 2003.</p>
  
  <p>Does anyone have an idea what I am doing wrong.</p>
  
  <p>I implemented the meeting request according to <a href="http://kobikobi.wordpress.com/2009/01/03/sending-meeting-requests-to-outlook-via-aspnet-mail-message/" rel="nofollow">sending-meeting-requests</a>
   .</p>
  
  <p>When sending the request I change some fields as required by <a href="http://www.ietf.org/rfc/rfc2446.txt" rel="nofollow">rfc2446</a>.</p>
  
  <p>Below is a combination of two messages.</p>
  
  <ol>
  <li>Lines appearing only in meeting creation </li>
  <li>Lines appearing only in meeting update – which does not work.</li>
  </ol>
  
  <p>Other lines appears in both messages.</p>
  
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  METHOD:REQUEST
  PRODID:-//ddaysoftware.com//NONSGML DDay.iCal 1.0//EN
  BEGIN:VEVENT
  ATTENDEE;CN=Attendee One;RSVP=TRUE:MAILTO:komerciala@email.eu
  ATTENDEE;CN=User Super;RSVP=TRUE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION
   ;CUTYPE=ORGANIZER;ORGANIZER=:MAILTO:master@email.com
  CLASS:PUBLIC
  COMMENT:
  1. CREATED:20120905T151819
  2. CREATED:20120905T151945
  DESCRIPTION:
  1. DTEND:20120905T163000
  2. DTEND:20120906T163000
  1. DTSTAMP:20120905T151819
  2. DTSTAMP:20120905T151945
  1. DTSTART:20120905T160000
  2. DTSTART:20120906T160000
  1. LAST-MODIFIED:20120905T151819
  2. LAST-MODIFIED:20120905T151945
  LOCATION:LJUBLJANA\, CESTA V MESTNI LOG   55
  ORGANIZER;CN=User Super:MAILTO:master@email.com
  PRIORITY:5
  1. SEQUENCE:0
  2. SEQUENCE:1
  SUMMARY:kioliko
  UID:5c6beaaf-1479-4028-b813-b9a66a2e3640
  BEGIN:VALARM
  ACTION:Display
  TRIGGER:-P1D
  END:VALARM
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  
  <p>Thank you!</p>