No. IPv4 is very reliable as it’s just a standard on how things should be done. The issue with IPv4 is that we as an Internet community are running out of public IP addresses. Some estimates are that we will run out of public IP addresses as soon as 2010. IPv6 fixes this problem by increasing the number of octets and the number of values in each octet.
Each octet is 0 to 255, or 8 bits in length— hence the term octet. With 4 octets you have 32 bits of address space (minus 2 addresses for a network and broadcast that’s beyond the scope here) or 4,294,967,296 (~4.2 Billion) addresses available. Essentially this is (2^32)-2 addresses. Some of this gets lost as this address space is divided up across the world into smaller pieces (2 addresses again, for the same reasons) and thus the real number becomes smaller.
Several ways of limiting this have been tried over the years and have been somewhat successful in prolonging having to move to IPv6, however, as more and more of our lives get “connected” to the internet more and more addresses are going to be needed.
IPv6 answers this call mainly becasue it’s 128 bits long, or (2^128)-2 addresses…. a number to huge to display on my calculator. (3.4028236692093846346337460743177e+38)