Latest version is breaking my sites

After updating to latest version 1.3 I get this error:

Warning: require_once(includes/add.php): failed to open stream: No such file or directory in /xxx/wp-content/plugins/simple-table-manager/simple-table-manager.php on line 55

Fatal error: require_once(): Failed opening required ‘includes/add.php’ (include_path=’.:/opt/alt/php74/usr/share/pear’) in /xxx/wp-content/plugins/simple-table-manager/simple-table-manager.php on line 55

includes folder is missing files or there are redundant require_once calls in simple-table-manager.php