Here are the steps to install the latest MariaDB 10.4 on the CentOS machine:
# MariaDB 10.4 CentOS repository list - created 2019-11-09 05:09 UTC# http://downloads.mariadb.org/mariadb/repositories/[mariadb]name = MariaDBbaseurl = http://yum.mariadb.org/10.4/centos7-amd64gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDBgpgcheck=1
sudo yum install MariaDB-server MariaDB-client
If the above steps give the error, check the link given in the first step.