Reply To: Empty fields and postmeta records with default values

add_filter("rwmb_group_value", function($new, $field, $old) {
if ($new == [[]]) $new = '';
return $new;
});

add_filter("rwmb_checkbox_value", function($new, $field, $old) {
if ($new == '0') $new = '';
return $new;
});