Index: init.php
--- init.php.orig
+++ init.php
@@ -8,5 +8,6 @@ define("LOAD_DEBUG", 2);
 define("LOAD_SOURCE", 3);
 // Defines the base path on the server, terminated by a slash
 define('BASE_PATH', realpath(__DIR__) . '/');
-define('UMAPI_PATH', '/usr/share/php-mapi');
+define('GROOT', realpath(implode(DIRECTORY_SEPARATOR, [__DIR__, '..'])));
+define('UMAPI_PATH', GROOT . DIRECTORY_SEPARATOR . 'grommunio-mapi-header-php');
 define('GROMOX_CONFIG_PATH', '/etc/gromox/');
