Today, the regional registrar APNIC, which is responsible for allocating IP addresses in Asia, has run out of freely available IPv4 addresses. This means that everyone who requests an IPv4 address in countries like China and India (where Internet usage is growing very rapidly) will not be able to get one. The next registrar that is predicted to exhaust their pool of IPv4 addresses is RIPE, which is responsible for IP address allocation in Europe. It’s notable that this has all happened faster than some originally predicted; it was thought that APNIC would exhaust its address pool about 6 months after the IANA assigned the last /8 blocks in early February. Instead, it happened just two months later.
It’s clear that the transition to IPv6 is really taking on some urgency, and Internet service providers are under increasing pressure to start providing IPv6 connectivity to their customers. While the exact timetable isn’t clear, there’s no question that developers need to plan for these changes and make sure that their software is capable of supporting both IPv4 and IPv6 networks.