VHCS is a Virtual Hosting Control System which has not been updated for years. It's the base of ispCP Omega back in 2006. Both systems are now incompatible but it is still possible to switch from VHCS 2.4.7 / 2.4.8 RC1 to ispCP Omega 1.0.0.
ispCP Omega (to simplify matters often called only ispCP) is a modern hosting Control panel that provides continued development.
ispCP is the Community, the Development Team and the Management Team behind ispCP Omega.