PHP Notice with WordPress 5.3 beta

Hi EDD,
I’m testing the WordPress 5.3 beta (currently 5.3-beta3-46455) and I get a PHP notice when Easy Digital Download plugin is active.
This is the notice:

Notice:  register_meta was called incorrectly. When registering an "array" meta type to show in the REST API, you must specify the schema for each array item in "show_in_rest.schema.items". Please see Debugging in WordPress for more information. (This message was added in version 5.3.0.) in ............../wp-includes/functions.php</b> on line 4898

I hope it will help to fix the problem before the release of WordPress 5.3