Read about it and download it
here.
It contains all the fixes from update rollup 1 and 2, plus:
KB
931328 - An integer is added to the end of the legacyExchangeDN attribute of a newly created mailbox in Exchange 2007
KB
930468 - The attachment is not displayed when you use Outlook 2003 to open an e-mail message that contains an attachment
KB
931842 - Error message when the sender or the receiver of a meeting request has a double-byte character set (DBCS) display name in Exchange Server 2007: "The requested property was not found"
KB
932207 - Error message when a user tries to open a forwarded message to accept or to deny a resource request in Exchange Server 2007: "Cannot open the free/busy information"
KB
932515 - You receive a 5.2.0 non-delivery report (NDR) message when you send an e-mail message to an Exchange 2007 server that is running the Isinteg.exe tool in a dismounted mailbox store
KB
934887 - DBCS characters are converted into two question marks in a forwarded e-mail message in Exchange 2007