I have customer who has office 2013 32bit and the Jabber meeting tab does not display the meetings for the day. The EWS intergration is working as the status does state in a meeting.
Office 2010 is not an issue but 2013 will be deployed soon. Tested office 2013 with Windows 7 and 8 and still has the same problem.
Be good to know if any one else is has this going or running into the same issue.
Checking the below link there is a difference with Office integration and Calendar Integration, while office 2013 is supported for integration its not listed for calendar integration.