This is very unfortunate change that this mailbox quota is no longer provided. I have requested this from Parallels support, but they just say that this should be requested from Horde community.
So far I have not found much help for this issue - the file /usr/share/psa-horde/imp/config/backends.php has some information about this feature in Horde5 / IMP6:
==================
* quota: (array) Use this if you want to display a user's quota status. Set
* to an empty value to disable quota status (DEFAULT).
*
* To enable, set the 'driver' key to the name of the driver. The 'params'
* key can contain optional configuration parameters.
*
* These 'params' keys are available for ALL drivers:
* - hide_when_unlimited: (boolean) True if you want to hide quota
* output when the server reports an unlimited
* quota.
* - format: (array) Specifies the formats of the quota messages displayed
* to the user. The array must contain the following four keys:
* - long
* - short
* - nolimit_long
* - nolimit_short
* The values for each of these keys are strings that will be
* passed through PHP's sprintf() command.
*
* The default values for each key is as follows (these might
* appear slightly different based on the current language;
* [UNIT] will be replaced with the value of the 'unit'
* parameter):
* - long: Quota status: %.2f [UNIT] / %.2f [UNIT] (%.2f%%)
* - nolimit_long: Quota status: %.2f [UNIT] / NO LIMIT
* - short: %.0f%% of %.0f [UNIT]
* - nolimit_short: %.0f [UNIT]
* - unit: (string) What storage unit the quota messages should be
* displayed in. One of:
* - GB
* - MB [DEFAULT]
* - KB
*
* These are the available drivers, along with their optional parameters:
* - hook: Use the quota hook to handle quotas (see imp/config/hooks.php).
* All parameters defined for this driver will be passed to the
* quota hook function.
* - imap: Use the IMAP QUOTA extension to handle quotas. The IMAP server
* server must support the QUOTAROOT command to use this driver.
* This is the RECOMMENDED way of handling quotas.
==================
The settings are found later on this file:
'quota' => array(
'driver' => 'imap',
'params' => array(
'hide_when_unlimited' => true,
'unit' => 'MB'
)
),
Still I have not found sollution how to enable quota. Whatever I changed seems not to work.
There is also this documentation
http://wiki.horde.org/AltQuota?referrer=HowTo but it seems to document how to use seperate quotas for IMAP folders and inbox. Not much help.
Currently it seems that with Plesk 11.5.30 mailbox quota can be checked by e-mail users only by logging into the Plesk with e-mail account. There you can see the quota bar on the same page where e-mail settings are modified. However, this is not very convenient for most users that they need to seperately login into Plesk just to see their mailbox quota.
Another option we're using is an old notification script provided from here:
http://forum.parallels.com/showthre...il-quota-notification-script-for-Plesk-9-3-10
If anyone can find any sollution for this issue, it would be highly appreciated. (The new Horde5 & IMP 6 seems modernly designed webmail inteface but this quota problem is a serious flaw in design. Also another issue is that user cannot no longer set the location of signature - to put it before quotations - which is a big problem for most of the users).