Hi Gary,

MAPI should support syncing categories.  EWS will still be used for Mac.

Categories should sync with EWS.  However, in order for the categories sync they must be used.  So if you create a category in web mail, you would need to use that category on a contact, appointment, or task in web mail.  Once it has been synced you should be able to use it in EWS going forward.  It would be the same thing if you create the category in your client, you would use it in the client and it should sync.