Huh… Where did Gertjan say you should do a fresh install?
A fresh install might be good idea if your on say 2.1 trying to go to 2.4 etc.. But you should never be there, you should upgrade asap after new versions are released.. 2.4.x+1 and p1 and p2, if they release, etc..
When they make a statement on if any upgrade caveats, etc.. But I had upgraded through all the 2.x to 2.4... I only went fresh install when I moved to sg4860 vs VM, etc.
Sorry English is not my language so I struggle a bit. Okay If an in place upgrade is possible there is nothing better than that.
Thanks.