Error notice after update

Hello,

I was using your plugin until today when I updated it to the latest version and I started getting a notice error in relation with WordPress 5.3 version. Please see the notice below:

Notice: add_submenu_page was called incorrectly. The seventh parameter passed to add_submenu_page() should be an integer representing menu position. Please see Debugging in WordPress for more information. (This message was added in version 5.3.0.) in /homepages/20/d772643783/htdocs/clickandbuilds/website/wp-includes/functions.php on line 4903

Is there any chance you can help me out fix this issue?

Any help would be highly appreciated.
Thanks