We have already published the list of the new PowerShell commands available in Microsoft Exchange 2013.
You can read about it here:
Exchange 2013 Powershell
It turns out that with the appearance of additional new commands to help you work with Exchange 2013 using Powershell also disappeared a few requests to use public folders. Probably has something to do with the change the organization of public folders in the new Exchange.
The following commands are no longer available in Exchange 2013:
If in the Microsoft Exchange Server 2010 we delete mailbox users by selecting the Remove or Disable, mailboxes and their contents are still stored in the Exchange database.
The difference between the operation Remove and Disable:
If you want to see a list of disconnected mailboxes in specified Exchange databasethen use the command:
Get-MailboxStatistics -Database "MailboxDatabase" | Where { $_.DisconnectDate -ne $null } | select DisplayName, DisconnectDate,TotalItemSize, TotalDeletedItemSize
to show all disconnected mailboxes in specified mailbox server:
Get-MailboxStatistics -Server MBXServer | where { $_.DisconnectDate -ne $null } | select DisplayName,DisconnectDate | sort DisconnectDate
English 
polski