[imp] how to disable imp quota in backends.local.php

[Samuel Wolf]

Hi,

I have a lot of the quota warnings in my horde.log:
2015-07-22T08:49:20+00:00 ERR: HORDE [imp] Speicherplatz-Kontingent  
konnte nicht gelesen werden [pid 25515 on line 47 of  
"/var/www/https/horde/imp/lib/Quota/Imap.php"]

How to disable the quota check in my backends.local.php?
Try $servers['advanced']['quota'] = false; but does not work.
What mean "Set to an empty value to disable quota status (DEFAULT)."?

<?php
$servers['imap']['disabled'] = true;
$servers['advanced']['disabled'] = false;
$servers['advanced']['hostspec'] = 'localhost';
$servers['advanced']['hordeauth'] = false;
$servers['advanced']['protocol'] = 'imap';
$servers['advanced']['port'] = 143;
$servers['advanced']['secure'] = 'false';
$servers['advanced']['acl'] = true;
$servers['advanced']['cache'] = false;
$servers['advanced']['autocreate_special'] = true;

Thanks.
Samuel