Yes, that Convention is a general commitment to international tax co-operation, and yes, it can - after many other international, legal, political and logistical steps and processes eventually lead to CRS years into the future, but it's not CRS. It's not even a formal commitment to CRS
(see some of the steps between there and CRS here: http://www.oecd.org/tax/automatic-e...al-exchange-relationships-crs-information.pdf)
Serbia hasn't even been asked to give a date for CRS yet.
If Serbia wants to achieve EU membership, it will have︀ to do CRS eventually, but with the way the Kosovo situation is proving a sticking︁ point there at the moment, then that and CRS is still some way off...