If you need to specify a specific answer use the following
sudo sh -c 'echo "y\n\ny\nN\nN\nN\nN\nN\nN\nN\nN\nN\nN\nN\n" | DEBIAN_FRONTEND=noninteractive /usr/bin/do-release-upgrade'
I agree though, the documentation should be a little better the functionality is there.
If you need to specify a specific answer use the following
sudo sh -c 'echo "y\n\ny\ nN\nN\nN\ nN\nN\nN\ nN\nN\nN\ nN\nN\n" | DEBIAN_ FRONTEND= noninteractive /usr/bin/ do-release- upgrade'
I agree though, the documentation should be a little better the functionality is there.