Information in Evolution get lost after editing in Contacts

1) Created contact with evolution

2) Converted contact on email server

3) contact on email server after adding a role in Kontact

The fields "Calendar" and "Free/Busy" in evolution are preserved in the conversion to the kolab xml format (see attachment b.eml). The content of the field "Calendar" is stored in a hidden field (because there is no support for it in the kolab format). The "Free/Busy" field is stored in the xml tag "free-busy-url", which is correct after the kolab specification [1].
As it can be seen in attachment c.eml, Kontact does dismiss two of three hidden fields (one is the "Calendar" field) and also the "free-busy-url" field. Here are two different bugs of Kontact.
Maybe it is possible to do a workaround for the hidden fields for Kontact (i will look at this). For the free-busy-url we can only hope that this will be fixed in Kontact someday.

[1] http://kolab.org/doc/kolabformat-2.0-html/c295.html

As explained before this are two Kontact bugs. Maybe it is possible to do a workaround for not losing most of the hidden fields by encoding them all in one xml element. As this is not a minor change and it is not sure if this will work, because we do not know the reason for the kontact bug, we should leave this fix to the kontact developers. Here is a quote from the kolab spec [1] that describes the constraint which is not implemented by kontact:

"If a client sees a tag it does not understand, this tag must be preserved and saved back to the file. This allows for client specific tags."

[1] http://kolab.org/doc/kolabformat-2.0-html/x147.html

I implemented the workaround for the Kolab Bug (like described below) in Version 0.0.7.
The field "Calendar" should now be preserved if the contact is edited in Kontact.

Also the value of the checkbox "Wants to receive HTML mail" should not be lost after editing the contact in Kontact

The functions work as expected. I close the bug.