https://www.simplepie.org/api/class-SimplePie_Net_IPv6.html
Class SimplePie_Net_IPv6 | SimplePie 1.3 API Documentation
ipv6 13 apiclasssimplepiedocumentation
https://www.govtech.com/archive/IPv6-Web-Domain-Support-Up-1900-Percent-in-2011.html
IPv6 Web Domain Support Up 1,900 Percent in 2011
Apr 23, 2021 - Domain registrar Go Daddy credited with spike in IPv6 adoption.
web domainsupport up1 900ipv6percent