Install Two versions

Hello
I Would like to know if I can install R14 again without uninstall V15?
I'm going to professional work and I prefer coming back to a secure version but I started a personal project on V15 I would like to tweak on free time.
So I need to have the two versions installed.
Thanks
I Would like to know if I can install R14 again without uninstall V15?
I'm going to professional work and I prefer coming back to a secure version but I started a personal project on V15 I would like to tweak on free time.
So I need to have the two versions installed.
Thanks