A Swiss VM hosting provider has a technical blog post about how to kill IPv4 completely on FreeBSD. That is to say, turning it completely off, not just preferring IPv6. They then solicit concrete solutions describing, along with a proof of concept, how to turn IPv4 completely off in other operating systems and allowing them to communicate with IPv6 only.
Earlier on SN:
Vint Cerf's Dream Do-Over: 2 Ways He'd Make the Internet Different (2016)
You have IPv6. Turn it on. (2016)
We've Killed IPv4! (2014)
(Score: 2) by VLM on Saturday January 19 2019, @02:50PM
Disclaimer entire post above was from memory and might work and might be secure for some values of "work" and "secure" you'd best hit up the mighty Google search bar if you're doing this for realzies but for discussion purposes its mostly accurate enough in the sense of hand grenades being close enough and so forth.