Is it possible to downgrade MySQL on a Plesk server?

MySQL does not support downgrading to an earlier database version, and Plesk on Linux servers does not natively support multiple local MySQL or MariaDB instances. This means if you need to use an older MySQL version, such as MySQL 5.6, or multiple database versions, alternative methods are necessary. Here’s an official Plesk article for further information: Is it possible to have multiple MySQL/MariaDB instances on Plesk for Linux?.

If different MySQL versions or multiple instances are required, here are two options:

1. Deploying a MySQL 5.6 Docker Container
   With Docker, you can run isolated applications and services. In this case, setting up a MySQL 5.6 container allows you to create a separate database server, distinct from Plesk’s default database. This enables you to maintain a specific MySQL version without impacting other Plesk services. Here’s a guide on how to install or upload a Docker image on a Plesk server.
2. Deploying an External MySQL Database Server and Adding it to Plesk Manually
   Alternatively, you can configure an external MySQL server with the required version and add it to Plesk as an additional database server. This approach allows you to use different MySQL versions for various databases or applications as needed. For guidance on adding and managing external database servers in Plesk, refer to Adding and Removing Database Servers in Plesk.