In Kerio MailServer, it is possible to set a quota for each email account that defines limits for number of messages and mailbox capacity (disc space).
Quota in Kerio WebMail Mini can be viewed at the page which is opened upon clicking on the root folder. It informs users about free capacity of their mailboxes. When the quota is reached, the user will receive a warning message including recommendation on deleting some messages. If the user ignores this warning, other mail will not be delivered to the mailbox since no more capacity is left.