caldav vs plain ics files

[Gavin McCullagh]

Hi,

I've been looking over calendaring as part of our proposed kolab setup
here.  Our clients are all Outlook and Thunderbird with the occasional
iphone, mutt, blackberry, etc.  With this in mind, I would prefer to deal
with widely supported standards like IMAP, CalDAV and ideally CardDAV.

Kolab obviously uses its own mail folder based storage for these tasks, so
I guess IMAP is effectively the protocol for them all.  I see that the
current version of kolab provides code to publish ICS calendars from those
and that Horde is preconfigured to use those.  I would be a little
concerned about the practicalities of using iCal across a large group of
users as calendars grow to large sizes.

Are there any plans to directly support CalDAV and/or CardDAV either in the
web interface or the server?  It seems that the Kolab server's success has
been founded at least partially in coherently integrating good existing
products (openldap, cyrus, horde, apache, php, ...).  While a decent
calendar server may have been hard to find a few years ago, there seem to
be candidates around now (apple calendar server, davical, ...).
Authenticating these against the kolab openldap database is relatively
straightforward -- though of course there's more involved than that.  

I could add davical to the Kolab setup myself, but it looks like Horde
doesn't support CalDAV which is a little awkward (although davical does
have fall-back support for iCal).

Any thoughts?

Gavin