Visit the following link and choose the desired version of MariaDB,https://downloads.mariadb.org/
Here are the commands to run to install MariaDB 10.4 from the MariaDB repository on your Ubuntu system:
sudo apt-get install software-properties-common
sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://mirrors.supportex.net/mariadb/repo/10.4/ubuntu bionic main'
Once the key is imported and the repository added you can install MariaDB 10.4 from the MariaDB repository with:
sudo apt update
sudo apt install mariadb-server
Reference: https://downloads.mariadb.org/mariadb/repositories/#distro=Ubuntu&distro_release=bionic--ubuntu_bionic&mirror=supportex&version=10.4
