Why does Plesk not send notifications that upgrade of MySQL/MariaDB is available?
Is the latest version of MySQL/MariaDB is available through System Updates menu in Plesk? When will it be available?
System Updates feature in Plesk uses the default OS package manager (yum in RHEL-based OS and apt in Debian and Ubuntu) to manage and update packages.
Therefore, Plesk is not responsible when the packages are updated in the OS vendor repositories: it does not manage settings for OS package managers.
When the new versions of the MySQL/MariaDB will appear in the OS vendor repositories, System Updates should send a notification (if notifications are enabled in Tools & Settings > System Updates > Settings > Notifications).
To clarify when MySQL/MariaDB package will be updated to the newer version in the OS vendor repository, contact maintainers of these repositories.