There were proposals at the time (1992!) for a backwards compatible version but they were rejected in favour of a clean slate approach. https://dl.acm.org/doi/

There were proposals at the time (1992!) for a backwards compatible version but they were rejected in favour of a clean slate approach. https://dl.acm.org/doi/pdf/10.17487/RFC1385 https://dl.acm.org/doi/pdf/10.17487/RFC1385