There are two versions of IP addresses and IPv6 (Internet Protocol version 6) is the newer and less used format.  IPv4 is the older and more common one.

IPv6 addresses are 128 bits divided into eight 16-bit blocks, then written in Hexadecimal with a colon (:) separating each block.  Hexadecimal uses base 16. Numbers 0-9 represent values 0-9, and letters A-F represent values 10-15.

They are the newer version of IP addresses, created to allow for a greater number of unique addresses as compared to IPv4.

Example:

2001:db8:a0b:12f0::1