Hello,
I converted openvz to lxc without any fails. When I press Start, container don`t start.
Version Ubuntu is 6.06 inside container.
I included support old version Ubuntu in file /usr/share/perl5/PVE/LXC/Setup/Ubuntu.pm
my $known_versions = {
'20.04' => 1, # focal LTS
'19.10' => 1, #...