If you recieve an email with a meeting invitation generated by an exchange server geary will show the message the user has send with the invitation but will not give you any sign that there might be more (like an invitation) it can not handle, except an attachment file with no name or extension.

At least i would expect to get a message that there is more geary can't handle or maybe show the time, date and place of the meeting. 
I can understand that it might be difficult to code the whole functionality of the exchange meeting handling (like response) but at least geary could let the user know that there is an invitation.

greetings,
pyri