So that means, if for example, a new squid proxy is out, i don't get that one? Can i install FC3 packages on FC2?
or even better question, what is going to happen if i change all the repo files from 2 to 3 and run apt/yum with a update/upgrade ?
You'll either end up running FC3 or severely damage your system. Can't tell which one though!
You might want to take a look here: http://www.brandonhutchinson.com/Upgrading_Red_Hat_Linux_with_yum.html
Paul.
