If a user upgrades to a new major release of MariaDB Connector/ODBC (e.g. MariaDB Connector/ODBC 3.0 to MariaDB Connector/ODBC 3.1), then Driver Manager will consider the new version to be "different" driver. The user will have to recreate their existing data source in Windows ODBC Data Source Administrator.
To save users from the hassle, it may be beneficial to implement a way to copy existing data sources when a user upgrades to a new major release of MariaDB Connector/ODBC. It should probably be optional.
Maybe the MSI installer could ask the user if they wanted to copy existing data sources during the installation process.