Edit cversion.ini File to Upgrade Windows 7 RTM Version from Windows 7 RC

Microsoft recently released the final build of Windows 7 to manufacture. The Windows 7 RTM version is available for Microsoft MSDN Subscribers now.

If you have installed previous Windows7 Beta versions or Windows 7 RC (release candidate) version, in order to install the RTM version of Windows 7 you have to remove the previous Win7 setup and make a clean install of Windows 7.

Unfortunately a Windows 7 upgrade from Windows 7 RC is not supported by Microsoft or the Windows 7 Setup.
But there is still a work-around if you do not want to reinstall all your programs again on the new Windows 7 RTM version.
This work around for upgrading Windows 7 RC or previous Windows 7 Beta builds to Win7 RTM can be achieved by editing the cversion.ini file.

The contents of the cversion.ini file contains only minimum build numbers for a safe upgrade of Windows 7 systems.
The original cversion.ini file has the build number 7233.0 for the minimum client OS build identifying the minimum Windows 7 build which can be officially upgraded to Windows 7 RTM (Released to Manufacture) edition.
So when we alter the cversion.ini for a suitable build number which will let you continue installation process, we can finish successfully installing Windows7.

How to Edit cversion.ini File

cversion.ini file is in sources folder of the root of Windows 7 installation media or Windows 7 setup DVD.

Open the cversion.ini file with notepad application.
The contents of the cversion.ini file is as follows :

[HostBuild]
MinClient=7233.0
MinServer=7100.0

All Windows 7 RC users should do is changing the line "MinClient=7233.0" as something like "MinClient=7000.0 for example.

After saving the cversion.ini file, the Microsoft Windows 7 RC setup will be enabled for a proper Windows 7 upgrade.

Note that you might experience some minor problems. But all is in your risk.
I can say as a last word, I would install a clean Windows 7 for a perfect Windows 7 installation.