nnBackup 2.28 b3 is available for download.
http://www.nncron.ru/download/nnbackup228b3.exe
Don't forget to take a look into history.txt! All the new features are briefly explained in http://www.nncron.ru/nnbackup/help/EN/command_line.htm . I'll try to put more details in the docs as fast as possible!