P.S. For anyone else to note, if you used address book sync in the past (i.e. in version 6.3.x.x and server 2.2 and earlier) and now have upgraded to the new version you must upgrade both Viewer and Server and then follow this address book sync upgrade guide. In a nutshell, you just need to export your existing address book, then set up address book sync anew - in the new version it is set up differently than before - and import your address book back into the system.
There will be a few minor fixes in the File Transfer mode. As for the speed with which the directories/folders are displayed, this is going to be fixed in one of the subsequent versions because it requires a little more work than a regular minor fix.