Downgrading your MySQL|MariaDB server to an older version is not always a good thing, specially if you or your customers used some features which are not available in the version to which you want downgrade. Therefore, this action must be carefully considered.
To downgrade to an older MySQL|MariaDB server version you must in order:
* Only needed in some cases (eg. when downgrading from MariaDB 10)
Once the steps above are done, you can run the i-MSCP installer as follow
# perl imscp-autoinstall -dar sql
and choose the MySQL|MariaDB server version to which you want downgrade.