Index: vendor/autoload.php
--- vendor/autoload.php.orig
+++ vendor/autoload.php
@@ -2,6 +2,9 @@
 
 // autoload.php @generated by Composer
 
+define('GTOPDIR', realpath(implode(DIRECTORY_SEPARATOR, [__DIR__, '..', '..'])));
+define('UMAPI_PATH', GTOPDIR . DIRECTORY_SEPARATOR . 'grommunio-mapi-header-php');
+
 require_once __DIR__ . '/composer/autoload_real.php';
 
 return ComposerAutoloaderInit153a56a781a72686b71399955d98204f::getLoader();