IPV4 is going to get replaced by IPv6 because of following reasons:
Growing no. of gadgets like mobile phones, laptops, palm-tops, desktops etc are used to connect to internet, so the format of IPv4 which is used to identify a gadget uniqely is running out of no.
This is because under IPv4 you have 4 byte or 32 bit addressing scheme, to handle this addressing scheme to uniqely identify every gadget it is suggested by the body to replace IPv4 by IPv6 which have wider range to addresses compare to IPV4.
There are still some factors to be considered to implement IPv6.
so lets hope to get the best so that for next few decades we can enjoy surfing without any conflicts
enjoy
