tl;dr: Google's measurements show IPv6 adoption has reached 50% of users accessing its services, though APNIC Labs' independently weighted measurements (using World Bank data to adjust for uneven ad sampling across economies) put the figure closer to 42%, with the two datasets effectively bracketing actual global capability. Adoption remains uneven, with newer entrants like Reliance Jio going IPv6-first while incumbents maximize IPv4 investments via NAT/CGNAT, and interoperability is handled at higher layers (TCP/UDP/QUIC) rather than at the IP layer itself.