Microsoft has released service pack 2 for exchange 2007 server and is available for download here Exchange 2007 SP2 includes the necessary schema extensions for Exchange server 2010.
Download the SP2 release notes from here
Take a note of the following before installing SP2, which is mentioned in the release notes.
- You need Windows 4.5 Installer before you can install SP2. Operating systems apart from Windows 2008 SP2 needs to download and install it.
- SP2 cannot be selectively uninstalled. You will have to uninstall entire exchange and install it again with a previous version.
- Install SP2 in the following order – CAS, UM, HUB, EDGE, MBX.
- You can upgrade servers running RTM as well as SP1 to SP2 version.
- You can upgrade either using the GUI or command line (Setup.com /mode:upgrade)
- After installing SP2, you can have 2007 in co-existence with 2010 RC (in your lab, ofcourse!)