New steam version

Hi everyone, I just wanted to know :If I have already installed Company of Heroes (new steam version), it is necessary to install the normal one (that comes with steam when I activate the serial key)?, and ..... should I uninstall my old COH (retail version)?. Thanks for any constructive replies.

Just install the new one and you are good to go. No need to install the retail version unless you want to play LAN game.

Ok, thank you. But what about my old coh (the one that I had before patch 2.700), it's necessary to keep having it?, or it is only useful to play LAN too?