Outlook not displaying ical RSVP buttons in email body - email

Question

Outlook 2016 or Outlook 365 is not recognizing attached ics file. The rsvp buttons are not showing in the email body but it does display correctly in gmail. I am able to download the ics file and import it into outlook.
BEGIN:VCALENDAR
PRODID:-//AroFlo PtyLtd
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:REQUEST
BEGIN:VEVENT
UID:eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzY2hlZHVsZV9pZCI6MCwic2NoZWRUe
XBlIjoiZXZlbnQiLCJncm91cGlkIjoxLCJvcmdfaWQiOjEzNywiU1ZBUk1DT05UUk9MSUQiOjM
xMTQ5LCJ1c2VyX2lkIjo3MTk1LCJ3b3JrcmVxdWVzdF9pZCI6MCwiZXZlbnRfaWQiOjU3MTUsI
mFsbG9jYXRpb25faWQiOjAsImNvbnRyb2xsaW5nb3JnaWQiOjEzNywidGVtcGxhdGVfaWQiOjA
sInRzX2dyb3VwX2lkIjowfQ.lVNWzJe1VbKsxdRJ2kCpLFUo2Wb1CqJ5Eom1nTgyewc
DTSTAMP:20180513T230757Z
DTSTART:20180514T050000Z
DTEND:20180514T073000Z
ORGANIZER;CN=Bri-Tech:mailto:test#email.com
CREATED:20180513T230757Z
LAST-MODIFIED:20180513T230757Z
SEQUENCE:0
SUMMARY:test event
DESCRIPTION:
X-ALT-DESC;FMTTYPE=text/html:
STATUS:CONFIRMED
TRANSP:OPAQUE
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP
=TRUE;CN=test user;X-NUM-GUESTS=0:mailto:test1#test.com
PRIORITY:5
CLASS:PUBLIC
CATEGORIES:AroFlo, event
END:VEVENT
END:VCALENDAR
Here is how the MIME email type is constructed
var m = new mail();
m.setSubject( 'event' );
m.setTo( test#email.com );
m.setFrom( "noreply#email.com" );
m.addPart( type="text/calendar", body="#icalFile#");
m.addParam( type="text/calendar", file="invite.ics", content="#icalFile#");
m.send();

Answer 1

Turns out the email MIME type wasn't added correctly. The code below now displays the RSVP buttons correctly.
In ColdFusion addParam() type can set more than one parameter.
m.addParam( type="text/calendar; charset=utf-8; method=REQUEST;"
, file="invite.ics"
, content="#icalFile#");