The Ubuntu Studio 20.04 Focal Fossa release notes include details on how to upgrade, as does this entry in the Ubuntu Community Help Wiki.
According to the release notes, you can upgrade if you are running Ubuntu Studio 18.04 or 19.10.
Preparations
Before you start, you should backup your data and make sure your current packages are up to date.
Most Ubuntu Studio 18.04 installs would have the Backports PPA enabled. If this is the case, you should remove it.
sudo apt install ppa-purge
sudo ppa-purge ppa:ubuntustudio-ppa/backports
Whether using a command line or GUI method, you'll likely be asked a few questions about keeping or replacing configuration files for packages
Command Line Upgrades
From a command prompt, type: sudo do-release-upgrade -d -m desktop
The -d
flag is needed until the first point release (eg 20.04.1) is available.