4.7 has only mysql, no mariadb.
5.3 has mariadb clients only. No mysql/mariadb server supported.
You can create and submit an extension, or post a request in the extension request thread.
You could also test the mysql extension from 4.7 in 5.3, and if it works post a notice in the thread for 4.x extensions that work in 5.x so it can be copied over.