sudo add-apt-repository ppa:scribus/ppa
sudo apt-get update
sudo apt-get install scribus

Reading package lists... Done
Building dependency tree
Reading state information... Done
Package scribus-ng is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'scribus-ng' has no installation candidate