The Internet Protocol (IP) is the language of the Internet. Electronic mail (Email), the World-Wide-Web (WWW) and the majority of computer based activities now operate over networks running the Internet Protocol.
IPv6 is the latest incarnation of the Internet Protocol. IPv4 is the current version. IPv4 is over twenty years old.
IPv6 brings the Internet Protocol into the twenty first century adding new features and consolidating the many changes that have been made to IPv4 over the years in order to keep it functioning. Most importantly IPv6 provides enough network addresses for the Internet to grow whereas IPv4 addresses are almost totally depleted.