upgrading from 7.1 to 7.3

Hi: I want to upgrade a server that is working with 7.1 to 7.3... can I do that without lossing my configuration and personal files (mail in /var/spool/mail, home directories, web files in my apache dir, my dansguardian files)...? Or I have to copy all the files, install loosing everything on the disk, and then copy my files back? Thanks, Raul