title: iCal outlook email compatibility problems
body: <p>I'm trying to generate an iCal file with multiple VEVENTs. I want to achieve one <code>.ics</code>-file, which has multiple appointments in it. It is important that these are not all-day appointments. So far, my generated file looks like this:</p>
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  PRODID: *** CENSORED ***
  METHOD:REQUEST
  X-MS-OLK-FORCEINSPECTOROPEN:1
  BEGIN:VEVENT
  UID:uuid-e4a9084f-91ea-4bc7-9bc0-3b2d6bec9030
  DTSTART:20211122T070000Z
  SEQUENCE:1
  TRANSP:TRANSPARENT
  STATUS:CONFIRMED
  DTEND:20211122T160000Z
  SUMMARY: TEXT
  ATTENDEE;CN=FirstName_LastName;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;RSVP=FALSE;PA
   RTSTAT=NEEDS-ACTION:MAILTO:*** CENSORED ***
  CLASS:PUBLIC
  DESCRIPTION: TEXT
  ORGANIZER;CN=*** CENSORED ***:MAILTO:*** CENSORED ***
  X-MICROSOFT-CDO-BUSYSTATUS:FREE
  X-MICROSOFT-CDO-INTENDEDSTATUS:FREE
  DTSTAMP:20211027T141024Z
  LAST-MODIFIED:20211027T141024Z
  END:VEVENT
  BEGIN:VEVENT
  UID:uuid-e4a9084f-91ea-4bc7-9bc0-3b2d6bec9030
  DTSTART:20211123T070000Z
  SEQUENCE:1
  TRANSP:TRANSPARENT
  STATUS:CONFIRMED
  DTEND:20211123T160000Z
  SUMMARY: TEXT
  ATTENDEE;CN=FirstName_LastName;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;RSVP=FALSE;PA
   RTSTAT=NEEDS-ACTION:MAILTO:*** CENSORED ***
  CLASS:PUBLIC
  DESCRIPTION: TEXT
  ORGANIZER;CN=*** CENSORED ***:MAILTO:*** CENSORED ***
  X-MICROSOFT-CDO-BUSYSTATUS:FREE
  X-MICROSOFT-CDO-INTENDEDSTATUS:FREE
  DTSTAMP:20211027T141024Z
  LAST-MODIFIED:20211027T141024Z
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  <p>So far so good. When I import this iCal-file to Google Calendar or even Outlook, both appointments are added correctly. The problem is when I attach the <code>.ics</code>-file to an email. Google Mail recognizes the attachment as as appointment and lets me Accept/Decline it in the email.</p>
  <p>When I open the exact same email in Outlook, Outlook doesnt even recognize the attachment as an appointment. I also have the problem, that only one VEVENT, the first one, is added to the outlook calendar.</p>
  <p>Is there something special about iCal attachments for Outlook? Can I do something to improve the compatiblity?</p>