diff -Naur roundcubemail-1.3.4.orig/program/include/iniset.php roundcubemail-1.3.4/program/include/iniset.php
--- roundcubemail-1.3.4.orig/program/include/iniset.php	2018-01-14 14:00:51.000000000 +0100
+++ roundcubemail-1.3.4/program/include/iniset.php	2018-02-04 23:47:34.217834831 +0100
@@ -29,7 +29,7 @@
 }
 
 if (!defined('RCMAIL_CONFIG_DIR')) {
-    define('RCMAIL_CONFIG_DIR', INSTALL_PATH . 'config');
+    define('RCMAIL_CONFIG_DIR', '/etc/roundcubemail');
 }
 
 if (!defined('RCUBE_LOCALIZATION_DIR')) {