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” 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.