@malik you will need to update your MySQL version before you update. Mautic 3 has a minimum requirement of MySQL 5.7. See also the ‘what’s new’ page on the docs.
According to the version compatibility,
MariaDB 10.2, MariaDB 10.3, and MariaDB 10.4 function as limited drop-in replacements for MySQL 5.7, as far as InnoDB is concerned. However, the implementation differences continue to grow in each new MariaDB version.
MariaDB 10.0 and MariaDB 10.1 function as limited drop-in replacements for MySQL 5.6, as far as InnoDB is concerned. However, there are some implementation differences in some features.
Source: MariaDB versus MySQL - Compatibility - MariaDB Knowledge Base
This explains the issue for MariaDB 10.0/10.1 users.