I have upgraded my account to cata with this method,BUT,i was stupid and I deleted mail that I got from blizzard regarding that upgrade,because I am not sure do we get some kind of serial key inside that mail or nothing? Or is serial key useless when you purchase digital download because your account is already upgraded to cataclysm so you dont need to enter any kind of serial numbers aka just log and play once 00:00 hits or you have to pop serial key even having purchased digital download?
Thank you in advance whoever can answer me this.