The obsession about "IPv6 only" has never made sense to me. Any decent firewall software will let you write rules that apply regardless of IP version. The "software complexity" argument is bunk... you already have v4 and v6 IP implementations in your OS, and every major OS has provided IP-version-agnostic socket interface code for much more than ten years. If you are using software that is IPv6-capable, it's very likely that it's using IP version agnostic library functions.
Unless stewardship of the Internet is wrested from the hands of the responsible, level-headed type of folks that run it now and transferred to the hands of folks who think nothing of making backwards-incompatible changes every six months, IPv4 won't stop running across the Internet within the lifetime of anyone who's currently reading HN. This delay is fine. The only thing about IPv4 that's a problem is that its address space is 32 bits wide. Had it been defined with a 128+ bit address space, we wouldn't have seen another version of IP on the Internet. Now that IPv6 is around to reduce address pressure, there's no big need to do anything about IPv4.
The obsession about "IPv6 only" has never made sense to me. Any decent firewall software will let you write rules that apply regardless of IP version. The "software complexity" argument is bunk... you already have v4 and v6 IP implementations in your OS, and every major OS has provided IP-version-agnostic socket interface code for much more than ten years. If you are using software that is IPv6-capable, it's very likely that it's using IP version agnostic library functions.
Unless stewardship of the Internet is wrested from the hands of the responsible, level-headed type of folks that run it now and transferred to the hands of folks who think nothing of making backwards-incompatible changes every six months, IPv4 won't stop running across the Internet within the lifetime of anyone who's currently reading HN. This delay is fine. The only thing about IPv4 that's a problem is that its address space is 32 bits wide. Had it been defined with a 128+ bit address space, we wouldn't have seen another version of IP on the Internet. Now that IPv6 is around to reduce address pressure, there's no big need to do anything about IPv4.