Kea's new thing is scaling up for very large/complex installations (multithreading, database backends, a fair amount of plugins for specialized use cases). Which almost nobody really needs to do, so it's a shame ISC dhcpd was discontinued before Kea was at full feature parity.
Not really; ISC dhcpd supported DHCPv6 just fine.
Kea's new thing is scaling up for very large/complex installations (multithreading, database backends, a fair amount of plugins for specialized use cases). Which almost nobody really needs to do, so it's a shame ISC dhcpd was discontinued before Kea was at full feature parity.