Kolab XML Format: The xCal/xCard based approach

[Thomas Koch]

Bernhard Reiter:
> Am Wednesday, 23. November 2011 15:14:37 schrieb Christian Mollekopf:
> > [...] the kolab format
> > is essentially already a subset of iCal/vCard (respectively their XML
> > representation).
> 
> No it isn't. The problem is that the difference are so subtle to many
> people that they will overlook them and implement problems. Using your own
> format is a stop-gap against this measure.

Hi Bernhard,

sorry for my naivety, just for clarification:

I've heard/read this argument now a couple of times, that kolab xml was 
invented, because iCal/vCard implementations were incompatible. But I couldn't 
find any list of these incompatibilites. On the other hand Georg Greve pointed 
out, that there is now the effort of calconnect.org to work out 
incompatibilites and have regular "plug-fests".

How does your justification of the kolab format differ from this XKCD?[1]

Since you have to implement kolab xml anyways in all clients, wouldn't it be 
less effort and more clever to fix those clients so that they implement the 
already existing standard correctly? Maybe older vCard/iCal may have had 
issues, but does the same still hold true for xCard/xCal?
Developing a standard is a lot of work. Wouldn't it be wiser to use already 
existing standards instead and collaborate with calconnect, like eGroupWare 
and DAViCal?
On the other hand, the Kolab format is regarded as underdocumented, lacking a 
test suite and tools.[2]

[1] http://xkcd.com/927/
[2] http://www.mail-archive.com/cyrus-devel@lists.andrew.cmu.edu/msg01877.html

Best regards,

Thomas Koch, http://www.koch.ro