RFC 8908: Captive Portal API

Nice, has this been implemented by any of the major WiFi or firewall vendors? I see the authors have Apple and Google contact info, so fair to assume this will be baked into smartphone operating systems, but when?

I see 1 forum post on appple developers forum describing it as broken in IOS14. I see 1 forum post describing it as broken in Mikrotik version. I get no google search hits when combining the RFC number with the words "Cisco" or "Aruba"