title: Update an event in Outlook 2007 with an iCalendar file
body: <p>There is <a href="https://stackoverflow.com/questions/45453/icalendar-and-event-updates-not-working-in-outlook">a previous thread with this question</a>, and hints at an answer, but I could not get it to work.</p>
  <p>I have an ICS file. It <a href="http://severinghaus.org/projects/icv/" rel="nofollow noreferrer">validates</a>. It looks like this:</p>
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  PRODID:-//WA//FRWEB//EN
  BEGIN:VEVENT
  UID:FRICAL201
  SEQUENCE:0
  DTSTAMP:20081108T151809Z
  DTSTART:20081109T121200
  SUMMARY:11/9/2008 12:12:00 PM TRIP FROM JFK AIRPORT (JFK)
  LOCATION:JFK AIRPORT (JFK)
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  <p>I double-click it and it goes into Outlook 2007 perfectly.
  Then, I double-click another ICS file that looks like this:</p>
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  PRODID:-//WA//FRWEB//EN
  BEGIN:VEVENT
  METHOD:REQUEST
  UID:FRICAL201
  SEQUENCE:1
  DTSTAMP:20081108T161809Z
  DTSTART:20081109T121300
  SUMMARY:11/9/2008 12:13:00 PM TRIP FROM JFK AIRPORT (JFK)
  LOCATION:JFK AIRPORT (JFK)
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  <p>As <a href="https://www.rfc-editor.org/rfc/rfc2446#page-19" rel="nofollow noreferrer">explained in the rfc</a>, the UID is the same and the sequence number is one greater, so I expect outlook to update my previous event entry, but all it does is insert a second one.</p>
  <p>How can I formulate the ICS file so that Outlook knows to update the event? The original poster in the thread I referenced above said he got it to respond with METHOD and ORGANIZER but in my experience METHOD has no effect and ORGANIZER causes undesirable behavior where Outlook wants to email the event to someone. I just want it to update the calendar.</p>