Application Compatibility: Windows Server 2008 Roles
Windows Server® 2008 is now completely componentized. The roles for Windows Server 2008 are now highly granular and optional. By default, no server roles are activated. Server roles from prior versions of Windows Server are not exactly the same in Windows Server 2008. For example, Web Server and Application Server were one role in Windows Server 2003 and are now split into two roles for Windows Server 2008
Installation instructions and scripts might break or produce improper results.
Installation instructions and scripts to install new servers will have to be updated.