//225delete_attachments_monthly_keep
// how many old months of attachments to keep?
$_prefs['delete_attachments_monthly_keep'] = array(
    'value' => 6,
    'locked' => false,
    'shared' => false,
    'type' => 'number',
    'desc' => _("Number of months to keep old linked attachments if deleting monthly."),
    'help' => 'prefs-delete_attachments_monthly_keep');

