text: The first major version of IP , now referred to as Internet Protocol Version 4 ( IPv4 ) is the dominant protocol of the Internet , although the successor , Internet Protocol Version 6 ( IPv6 ) is in active , growing deployment worldwide .
simplified: At the moment there are two versions of the Internet Protocol . One is called IP Version 4 ( IPv4 ) , the other one is called IP Version 6 ( IPv6 ) .