The latest Ubuntu release, 20.04, marks an opportunity for both LTS users and people on the previous 19.10 release to update Ubuntu and take advantage of the latest features.
An existing Ubuntu 18.04 LTS or 19.10 install with root privileges.
Run your Ubuntu Update
Before you do anything, make sure that your system is already up-to-date.
$ sudo apt update
$ sudo apt upgrade
$ sudo apt dist-upgrade
This will help to ensure that the difference between packages is as small as possible.
$ sudo apt autoremove
How to Upgrade Ubuntu
Ubuntu have developed their own automatic way of upgrading between releases. It essentially scripts the traditional Debian approach. This way, you can set it up to upgrade and walk away. Ubuntu will handle the rest.
Please Note: Upgrades from 19.10 will not be enabled until a few days after 20.04’s release. Upgrades from 18.04 LTS will not be enabled until a few days after the 20.04.1 release expected in late July 2020. There are no offline upgrade options for Ubuntu Desktop and Ubuntu Server.
$ sudo apt install update-manager-core
When that finishes, run the Ubuntu upgrade utility.
$ sudo do-release-upgrade
If you’re doing this too soon, it will tell you that there is
No new release found. In that case, and at your own risk, add the
-d flag at the end of the command to force the upgrade. For more information read the below “No new release found” section.
$ sudo do-release-upgrade -d
Then it can takes at least 1 hour to complete…