“Windows Server Migration Tool” allows administrators to migrate some Server Roles, OS settings, files, shares, and other data from computers running a previous editions of Windows Server (you can also migrate from Windows server 2012) to Windows Server 2012.
This tool is useful if you have computers running Windows Server 2003 or Windows Server 2008 with 32-bit processors that you cannot upgrade to Windows Server 2012.
To use Windows Server Migration Tools you should:
1-Install Windows Migration Tools on the Destination Server (Windows Server 2012)
2-Create a deployment folders on the Destination Server
3-Copy the created deployment folders to the Source Server (Previous Windows Server edition)
4-Register Windows Migration Tools on the Source Server