iCalendar (ics) versions and various calendar clients (Outlook, iCal, Lotus Notes) - what works and what doesn't?

I'm working on a web application that allows users to create a calendar of events, then download those events into their calendar program of choice (e.g., Outlo开发者_如何学Cok, Lotus Notes, iCal, Google Calendar, etc.)

The web app outputs the event data as an attachment in iCalendar (ics) format.

I'm running into a variety of problems...

1. If I use "VERSION:1.0", Outlook 2003 will recognize and import the attachment. However, Apple iCal will not. If it's "VERSION:2.0", iCal works, but Outlook 2003 will not.

2. If the attachment has more than one event (VEVENT), then Outlook 2003 only imports the first event, unless the user uses Outlook's import function.

3. I don't have Lotus Notes, or multiple versions of Outlook (2007, 2010), so I can't how those behave easily.

I don't mind having to implement a little dialog that asks the user what calendar program they use so I can customize the output accordingly. However, I don't know what each of the major programs supports or requires.

Has anyone found a resource that lists, by calendar program, what works and what doesn't? E.g., does Outlook 2007 or 2010 support "VERSION:1.0"? Is there a way to get Outlook 2003 to support "VERSION:2.0", or handle multiple events? What does Lotus Notes support? What about Yahoo and Google?

I don't need to support EVERY program, but I'd like to support as many of the major ones as possible.

Many thanks in advance!

Regarding Lotus Notes, you can download a trial version of the Notes client software from the IBM site, which may be all you really need to test your application. Notes can import ical entries through an Import menu, or dragging and dropping the iCal file into the Notes client. (If you need to do further Notes-specific development, you can also download a free version of the "Domino Designer" software from the IBM web site - IBM makes the Designer software available free for single machine use - no server access.)

There is a KBase article on the IBM site with some details of iCal support in the latest version of Notes (8.5) - http://www.ibm.com/developerworks/lotus/library/notes85-icalendar/index.html