I registered on this site and downloaded the upgrade from Pro-52 to Pro-53. When I run the upgrade, it asks for my serial number in 3 parts. 3 numbers, then 5 numbers, then 5 numbers again. The only serial number I can find for my pro-52 is on the mail-in registration form, and it comes in a single 9 digit number. I cannot enter my serial number into the 13 alloted spaces, it tells me that my serial number is incorrect.
To run Pro-53 you need a new serial number. Please go ahead and request one from
www.nativeinstruments.de just above the actual update link.