Using the instructions provided by IONOS to upgrade your MySQL database from 5.5 to 5.7 did not work for me. Unfortunately, once I got to the step to import the old database into the new, I got a 1044 – Access Denied error. IONOS recommends deleting all statements that begin with CREATE or USE in the exported database prior to attempting to import. This is not helpful as then your tables will not be recreated in the new database. The fix is to search for all occurrences of your database name (db402946823 in my case) in the exported database file and replace with the new database name. After that, the import went off without a hitch.
If you are using the database for WordPress, don’t forget to update the settings in wp-config.php to match the new database so that it doesn’t continue using the old. IONOS makes this simple with the Webspace tool.