php - Send ics calendar invite using Swift Mailer

Download full source code from here

This code works fine with Gmail, Yahoo, Office 365, Outlook & Others. Some screenshots of different mail system are below.

Sample Request

BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTART:20170118T134600Z
DTEND:20170118T141600Z
DTSTAMP:20170118T132600Z
UID:PKMf3c65f6ac8d3c3e1a99f3464acb6d11723400878
ORGANIZER;CN=email@organizer.pkm:mailto:email@organizer.pkm
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;
    CN=pritomkucse@yahoo.com;X-NUM-GUESTS=0:mailto:pritomkucse@yahoo.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;
    CN=pritomkucse@gmail.com;X-NUM-GUESTS=0:mailto:pritomkucse@gmail.com
CLASS:PRIVATE
DESCRIPTION:Some Calendar Description
LOCATION:Some Calendar Location
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Some Calendar Summary
TRANSP:OPAQUE
PRIORITY:5
BEGIN:VALARM
DESCRIPTION:REMINDER
TRIGGER:-P0DT0H10M0S
ACTION:DISPLAY
END:VALARM
END:VEVENT
END:VCALENDAR

Sample response

Google Email Inbox View:

Google Calendar Box View:

Yahoo Email Inbox View:

Yahoo Calendar Box View:

Office 365 Email Inbox View:

Customized Email Inbox View

Outlook 2013 Email Inbox View

Calendar Reminder Notification Example