Microsoft has released Update Rollup 3 for Microsoft Exchange Server 2007 Service Pack 3 (SP3).
We can refer to the article Description of Update Rollup 3 for Exchange Server 2007 Service Pack 3 to know issues that the update rollup fixes And download it from Download the Exchange2007-KB2492691-EN package now.
Before you install an update rollup or a service pack, visit the following Microsoft website for prerequisites, installation instructions and known issues:
How to Install the Latest Service Pack or Update Rollup for Exchange Server 2007 (http://technet.microsoft.com/en-us/library/ee221147(EXCHG.80).aspx)
For a list of update rollups that apply to Exchange Server 2007 RTM, Exchange Server 2007 SP1 or to Exchange Server 2007 SP2, the following Microsoft website:
Here are few important issues related to Exchange development APIs fixed in the release of RU3 :
2450078 (http://support.microsoft.com/kb/2450078/ ) The sent time in an email message body is incorrect when you reply or forward the email message by using an EWS application in an Exchange Server 2007 environment.
2445129 (http://support.microsoft.com/kb/2445129/ ) The W3WP.exe process may crash when a WebDAV client connects to an Exchange Server 2007 server
2394853 (http://support.microsoft.com/kb/2394853/ ) The returned URL is incorrect when you use the WebDAV "X-MS-ENUMATTS" method to enumerate an attachment in an Exchange Server 2007 environment
2267661 (http://support.microsoft.com/kb/2267661/ ) Some body parts of a message are displayed as attachments when an Exchange Server 2007 user sends the message by using a third-party mail client
955480 (http://support.microsoft.com/kb/955480/ ) A meeting request is stamped as Busy instead of Tentative when it is sent from an external user to an Exchange Server 2007 user