Meeting Request, Response and Cancellation messages are not updated in Sent Items folder

Problem:

Meeting Request, Meeting Response and Meeting Cancellation messages are not updated in the Sent Items folder.

Solution:

For such items (Meeting Request, Meeting Response and Meeting Cancellation) the signature is added only for those outgoing from the Exchange Server, and not the ones already saved in the Sent Items folder. The reason for this is that items such as Meeting Request, Response and Cancellation that have already been sent cannot be updated.

Exchange Web Service (EWS), which is responsible for updating items, is not capable of updating these specific messages. Microsoft is referring to this as a bug of EWS service.