You may or may not have heard: the internet is undergoing a revolution! The truth is, the change has been underway for well over a decade; it's just that not a lot of people know about it. What is this monumental change? We are moving from IPv4 to IPv6. Ok, maybe it's not all that exciting, but the change is still happening, and it is starting to have a few ripple down effects.
It is likely that on your travels through the internet you have stumbled across numbers of the form 18.104.22.168. That is an IP address, the IPv4 form, and every computer connected to the internet has one. Much like you have a unique phone number that people can contact you on, your computer has a unique IP address through which websites can communicate. IPv6 is simply an alternative way of creating a unique address.
Unfortunately, IPv4 uses 32-bit encoding, meaning it has 2^32 (around 4.3 billion) different combinations, and we are running out. In fact, the last block of IPv4 addresses was assigned way back in 2011, so we are starting to scrape the barrel to keep going with IPv4. That is where IPv6 comes in, which uses 128-bit encoding, which has over 70 octillion (a vast number) times the number of addresses as IPv4.
Unfortunately, while it is eventually going to be necessary to deprecate IPv4, the process is complicated and costly, and so companies would much rather stick with what they know and spend their money elsewhere. The problem lies in that select gateways are needed to convert between the two formats, and so the two systems effectively run in parallel. As such, many web hosting services and ISPs do not currently support the new protocol.
Even though uptake of IPv6 is slow, it is essential if the internet is to keep operating the way we have come to expect. In time, companies will be forced to upgrade their systems to incorporate IPv6, although the likely truth is that many customers will be completely oblivious to the change, and the web will continue to function just as it does now.