For a customers website which has an integrated calendar we also created an iCal URL which the users can use to import the calendar into their own client. The problem I'm facing is, that the calendar does NOT create any notifications on a mac-calendar and I really don't have a clue why.
I have checked with my private gmail-calendar ics and could not find any relevant field that I'm missing. Here is what our code generates:
BEGIN:VCALENDAR
CALSCALE:GREGORIAN
METHOD:PUBLISH
PRODID:-//github.com/rianjs/ical.net//NONSGML ical.net 4.0//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:W. Europe Standard Time
X-LIC-LOCATION:Europe/Berlin
BEGIN:STANDARD
DTSTART:20161030T030000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20170326T020000
RRULE:FREQ=YEARLY;BYDAY=4SU;BYMONTH=3
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
CREATED:20180504T130321
DESCRIPTION:Appointment2Annotiation
DTEND:20180514T130320
DTSTAMP:20181001T125831Z
DTSTART:20180513T130320
LOCATION:Teststraße 12\, 4050 Traun
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Appointment2 - NACHNAME 54 Vorname 54
TRANSP:OPAQUE
UID:dd70978d-bbf7-4ff3-b7b3-00a37c2772fc
END:VEVENT
...
some more events
...
BEGIN:VEVENT
CREATED:20180504T130321
DESCRIPTION:Vorname 34\, Nachname 34\, +43 664 933 934\, [email protected]\n
SVorname 34\, SNachname 34\, \, \n \nHochzeit\n20.10.2018 00:00:00 - 22.1
0.2018 00:00:00 Teststraße 12\, 4050 Traun\n \nInterne Test Notizen...\n
DTEND;VALUE=DATE:20181022
DTSTAMP:20181001T125831Z
DTSTART;VALUE=DATE:20181020
LOCATION:Teststraße 12\, 4050 Traun
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:NACHNAME 34 Vorname 34 - Hochzeit
TRANSP:OPAQUE
UID:0e57c72f-2b71-4639-b967-15f1295e9d71
END:VEVENT
END:VCALENDAR
Anybody got some suggestions what I may be missing or doing wrong?
After a very long night I finally found the answer. The main problem was solved by simply changing the format of the dates to UTC. The resulting ics structure is:
BEGIN:VCALENDAR
CALSCALE:GREGORIAN
METHOD:PUBLISH
PRODID:-//github.com/rianjs/ical.net//NONSGML ical.net 4.0//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:W. Europe Standard Time
X-LIC-LOCATION:Europe/Berlin
BEGIN:STANDARD
DTSTART:20161030T030000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20170326T020000
RRULE:FREQ=YEARLY;BYDAY=4SU;BYMONTH=3
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
CREATED:20181001T082504Z
DESCRIPTION:Max\, Mustermann\, \, [email protected]\n \nHochzeit\
n10.10.2018 13:00:00 - 10.10.2018 17:00:00 Hochzeitsanprobe - Musterstraß
e 13\n \n\n
DTEND:20181010T150000Z
DTSTAMP:20181002T082215Z
DTSTART:20181010T110000Z
LAST-MODIFIED:20181001T082504Z
LOCATION:Hochzeitsanprobe - Musterstraße 13
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:MUSTERMANN Max - Hochzeit
TRANSP:OPAQUE
UID:56f627db-a84f-4901-bb14-a6f513854a52
END:VEVENT
END:VCALENDAR
Hope this helps someone in the future