telnet 0.17+2.4-2ubuntu2 (amd64 binary) in ubuntu mantic

 This package will force a switch from the old netkit telnet implementation
 to the inetutils-telnet one, which is an upstream maintained project.
 .
 This package can be safely removed once it has been upgraded, as
 inetutils-telnet provides a matching virtual package. It will stop being
 provided after Debian bookworm's release.
 .
 If you want to keep using the netkit implementation, then install
 telnet-ssl instead.