Hassan, it's always possible, but the truth is is it worth it?
V6 means the site is 5+ years old, do you really want to spend all the effort to upgrade an old design and implementation to the latest? What do you gain from that? Only the basic functions that was available back in V6. All the new features still need new implementations.
Our typical recommendation for clients that have a site running on V7 or earlier is to consider redesign and implementation with the latest version.