Index: installer/config.php
===================================================================
--- installer/config.php	(revision 7d7f67dde1ef87826bde757bce36bb448aae14e0)
+++ installer/config.php	(revision ffae15e5fcde50cf8c1b168fa313f4ec3454a693)
@@ -540,4 +540,19 @@
 </dd>
 
+<dt class="propname">mime_param_folding <span class="userconf">*</span></dt>
+<dd>
+<?php
+
+$select_param_folding = new html_select(array('name' => '_mime_param_folding', 'id' => "cfgmimeparamfolding"));
+$select_param_folding->add('Full RFC 2231 (Roundcube, Thunderbird)', '0'); 
+$select_param_folding->add('RFC 2047/2231 (MS Outlook, OE)', '1');
+$select_param_folding->add('Full RFC 2047 (deprecated)', '2');
+
+echo $select_param_folding->show(intval($RCI->getprop('mime_param_folding')));
+
+?>
+<div>How to encode attachment long/non-ascii names</div>
+</dd>
+
 </dl>