Hello this is my situation:
Plugin 1 (need Metabox 4.7.1):
define( 'RWMB_VER', '4.7.1' ); // Example
require_once 'plugin-1/path-to-meta-box/inc/loader.php';
$loader = new RWMB_Loader;
$loader->init();
Plugin 2 (need Metabox 4.9.8):
define( 'RWMB_VER', '4.9.8' ); // Example
require_once 'plugin-2/path-to-meta-box/inc/loader.php';
$loader = new RWMB_Loader;
$loader->init();
But this can not work because the class RWMB_Loader already exists.
Thank you very much