The protocols and APIs the MAPI Connector implements are not the Internet standards, but API from the Microsoft® Corporation. Those APIs are not fully documented, and as a result, some minor client (Outlook) functions may be unavailable. CommuniGate Systems is working on solving these problems, and the MAPI Connector updates are released on a regular basis.
The special Known MAPI Problems site lists all reported and known problems and provides the status update on them. Please consult this site first if you have any problem with the MAPI Connector functionality.