How to upgrade ubuntu OS to a newer version

NOTE: Backup all your services, databases, documents, etc. The upgrade process may not work as expected and can be hard to access the data again

1. Update packages and check whether upgrades may work as expected

$ sudo apt update 

2. Upgrade apt packages

$ sudo apt upgrade -y

3. Clean unused packages

$ sudo apt autoremove && sudo apt autoclean && sudo apt autopurge

OR

$ sudo apt autoremove && sudo apt autoclean && sudo apt autoremove --purge

4. Reboot machine

$ sudo reboot

5. Install upgrade manager

$ sudo apt install update-manager-core

6. Check the next available version

$ sudo do-release-upgrade -c

7. Install all available updates for your release before upgrading

$ sudo apt dist-upgrade

8. Perform upgrade

$ sudo do-release-upgrade

9. Depending on how reconfigured was the servers, the updater will prompt question to be answered. See screen shots bellow for some examples