Manos

And Thank you for your reply!
The code is this one and it worked before the updates:

add_filter( ‘rwmb_meta_boxes’, ‘your_prefix_register_meta_boxes’ );

function your_prefix_register_meta_boxes( $meta_boxes )
{
$prefix = ‘dirlis_’;

$meta_boxes[] = array(
‘title’ => __( ‘Φωτογραφίες Προϊόντων’, ‘your-prefix’ ),
‘fields’ => array(

array(
‘name’ => __( ‘Image Advanced Upload’, ‘your-prefix’ ),
‘id’ => “{$prefix}imgadv”,
‘type’ => ‘image_advanced’,
‘max_file_uploads’ => 4,
)
),
);
return $meta_boxes;
}