Could you give a stack trace please? (if it's available of course). You get this error when pulling metadata for tables or also for other elements?
What I gather from DevArt's website is that their v8.0 connector is required for mysql v8. Nevertheless, what we're doing is:
DESCRIBE tablename
as the query, and then consume the resultset as a datatable. We have to check whether that gives a different resultset on mysql 8 as it does on previous versions or that the devart connector does/doesn't work with that...
(edit) according to the mysql 8 docs, 'describe' returns the info like show_columns does, which is what the driver expects. Odd... (however again, it might be the values returned by the devart connector are not correct as their connector v5.x might not be compatible with v8 (as they explicitly state mysql 8 support is available through their v8 connector))