On Monday, IANA fulfilled its last request for /8 blocks of IPv4 addresses. This triggers the IANA “[Global Policy for the Allocation of the Remaining IPv4 Address Space](http://www.icann.org/en/general/allocation-remaining- ipv4-space.htm)” exhaustion phase. This doesn’t mean there are no more available IPv4 addresses - APNIC just got two /8s on top of whatever they already have, and expect to be rationing them out for at least another 5 years. ARIN reported that they have almost five /8s worth of IPv4 addresses left to allocate.
So it’s probably not worth retro-fitting existing codebases to support IPv6 just yet. Most ISPs and consumer routers still don’t support IPv6. But I expect that to start changing in the coming year or two, especially after the attention this week’s announcement received.