Problems with IMAP-Shared Folders and suggestion for implementing freebusy for Horde-Style servers

Im evaluating eM for an interested client as replacement for Thunderbird because of their lack of correctly implemention of CalDAV and CardDAV.
Which works great in eMC
But I run into 2 “showstoppers”.
The client is using Kolab 16 - Server as a groupware-service and there the shared folders don’t  work caused in a incomplete IMAP implementation in eMC.
These “bug” is often discussed in the forum, but not fixed until today.
I’ve analysed the IMAP Log of the connection of eMC toward the Cyrus-IMAP-Server,
and have seen that you are using “%” as asterisc in the LIST command.
With this asterisc Cyrus (and even dovecot) delivers an incomplete folder List.
I’ve tried this out with a manual test against the IMAP-Port in a simple telnet-session.
If you would change “%” to “*” the server delivers a full folder listing.
All other clients I’ve tested are doing LIST also with the “*” asterisc.
There is a difference between % and *
Where % delivers only the top-level mailboxes, * delivers a full list.The “failure” in the missbehaving with shared-folder and other-users mailboxes seems to be in the way like dovecot, cyrus and so on do handle these special folders.
The LIST “” “%” delivers for these “HasNoChildren” so there is no deeper scan anymore.
And eMC does not see the folders behind, because ist thinks there is no substructure.
This can be fixed quick and dirty, by taking a full list, or by list with “*” if there is a shared-folder and or other-users  in namespace.

Another showstopper is the lack of freebusy for opensource colaboration systems like Kolab, Horde, openexchange or OwnCloud.
This should be relativ simple, because the way to get the free-busy data on such systems is quite simple. You have to make a simple get on for example https://server.url/freebusy/j.doe@example.org authenticated by the same credantials as for the CalDAV-Account,
and get back a reply in the following format:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//kolab.org//NONSGML Kolab Free-Busy Service 3.2//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VFREEBUSY
DTSTART:20180411T000000Z
DTEND:20190612T000000Z
DTSTAMP:20180606T105158ZFREEBUSY;FBTYPE=BUSY:20180529T113000Z/20180529T120000ZFREEBUSY;FBTYPE=BUSY:20180503T120000Z/20180503T133000ZFREEBUSY;FBTYPE=BUSY:20180530T123000Z/20180530T130000Z
FREEBUSY;FBTYPE=BUSY:20180531T133000Z/20180531T140000Z
FREEBUSY;FBTYPE=BUSY:20180601T143000Z/20180601T150000Z
FREEBUSY;FBTYPE=BUSY-TENTATIVE:20180615T103020Z/20180615T150020Z
UID:201806061251-cf2ea5632d3e4a05
ORGANIZER:mailto:j.doe@example.org
END:VFREEBUSY
END:VCALENDAR
This should be quite easier then to implement freebusy on Exchange.
If this would work for us, and the IMAP-shared-folder issue would be fixedeMC would become a real alternative, cause the userinterface is great.

Has there been any development on this?
I have some users that are looking for an Outlook alternative and eMclient looks very good except that IMAP shared folders are no where to be seen!!

Our ISP uses Mdaemon email server.

Regards

Tomas