Leafer,
Kronolith is the calendar portion of the horde product. Mitel has included the mail (imp) and contacts (turba) with 5.5. Kronolith requires the 2.1 version of the horde framework, as does nag (tasks), and mnemo (notes). I have installed all of these on a test 5.5 server and they will work. The only issue is that you have to template the system to get the apps to keep functioning. If not, then a signal-event console-save will blow it all up. That is my same issue. I am hoping Mitel will include the 2.1 framework in a future blade, then I may try looking at templating the rest.
Mitel's groupware product is based on TWIG.
JB