Upgrade Ubuntu Release

#!/bin/bash
set -e

# https://linuxconfig.org/how-to-upgrade-to-ubuntu-18-04-lts-bionic-beaver

sudo apt update  -y
sudo apt upgrade -y
sudo apt dist-upgrade -y

sudo apt autoremove -y

sudo apt install update-manager-core -y

sudo reboot

sudo do-release-upgrade

# lxc exec NAME -- script /dev/null -c do-release-upgrade

# container:~# script /dev/null
# do-release-upgrade

a2enmod php7.2

You may need to update postgres and other apps

sudo pg_dropcluster 10 main --stop
sudo pg_upgradecluster 9.5 main
sudo pg_dropcluster 9.5 main
apt purge postgresql-9.5