Ok, I found it, thx.
But note from CHANGES_AND_HINTS.txt:
*** INSTRUCTIONS FOR UPGRADING FROM 12.2 ***
Also note that upgrading from 12.2 to 13.0 (64bit) is not supported.
But how about upgrading from -current x86 to 64-bit? It's rater switching between platforms than upgrading...
I know, that the best way is to reinstall from scratch, but I don't have any available disks to make backup of my files and data.
If I install from scratch OVER existing installation without re-formating the drive, is it possible to keep my data secure?