How to update to the 18.10 beta? [duplicate]

Pre-requisites:

sudo apt update 
sudo apt upgrade
sudo apt dist-upgrade
sudo apt autoremove

Those will make sure your current system is up to date.

Edit /etc/update-manager/release-upgrades and set Prompt=normal to avoid the "No new release found message."

This will start the upgrade:

sudo do-release-upgrade -d

Big fat warnings:

• Please do not do this on a production server. 18.10 is not ready for general usage and breaking your system is more likely than having a working system. Every new update might break something.
• If you have personal data do make a backup every day and save them all. At some point you might need to re-install as every update could break your boot procedure. Knowing a little not more then average about the inner workings of Ubuntu so the base system, Linux, systemd, the boot process would be good to have.
• Biggest problem probably will be 3rd party drivers. I would remove them and stick to the open source versions when upgrading and re-enable them when there is a working newer system.