Difference between iCalendar (.ics) and the vCalendar (.vcs)
Solution 1:
iCalendar was based on a vCalendar and Outlook 2007 handles both formats well so it doesn't really matters which one you choose.
I'm not sure if this stands for Outlook 2003. I guess you should give it a try.
Outlook's default calendar format is iCalendar (*.ics)
Solution 2:
Both .ics and .vcs files are in ASCII. If you use "Save As" option to save a calendar entry (Appt, Meeting Request/Response/Postpone/Cancel and etc) in both .ics and .vcs format and use vimdiff, you can easily see the difference.
Both .vcs (vCal) and .ics (iCal) belongs to the same VCALENDAR camp, but .vcs file shows "VERSION:1.0" whereas .ics file uses "VERSION:2.0".
The spec for vCalendar v1.0 can be found at http://www.imc.org/pdi/pdiproddev.html. The spec for iCalendar (vCalendar v2.0) is in RFC5545. In general, the newer is better, and that is true for Outlook 2007 and onward, but not for Outlook 2003.
For Outlook 2003, the behavior is peculiar. It can save the same calendar entry in both .ics and .vcs format, but it only read & display .vcs file correctly. It can read .ics file but it omits some fields and does not display it in calendar mode. My guess is that back then Microsoft wanted to provide .ics to be compatible with Mac's iCal but not quite committed to v2.0 yet.
So I would say for Outlook 2003, .vcs is the native format.
Solution 3:
You can try VCS to ICS file converter (Java, works with Windows, Mac, Linux etc.). It has the feature of parsing events and todos. You can convert the VCS generated by your Nokia phone, with bluetooth export or via nbuexplorer.
- Complete support for UTF-8
- Quoted-printable encoded strings
- Completely open source code (GPLv3 and Apache 2.0)
- Standard iCalendar v2.0 output
- Encodes multiple files at once (only one event per file)
- Compatible with Android, iOS, Mozilla Lightning/Sunbird, Google Calendar and others
- Multiplatform