MariaDB upgrade option is missing under Tools & Settings > Database Servers

Symptoms

• The Tools & Settings > Database servers tab does not contain the option to upgrade the MariaDB service to version 11.4.
• The current MariaDB version is 10.11

Cause

The automatic upgrade feature supports the upgrade to MariaDB 10.11 only. 
The ability to upgrade the MariaDB 11.4 will be realised in future Plesk updates. 
Please follow the Plesk change log. 

Resolution

Until the feature is implemented the MariaDB can be upgraded manually using the steps from the article "Ugrade MariaDB" section "Manual procedure"