The steps that were outlined for upgrading the Windows 7 beta release to release candidate were the following:
- Download the ISO as you did previously and burn the ISO to a DVD.
- Copy the whole image to a storage location you wish to run the upgrade from.
- Browse to the sources directory.
- Open the file cversion.ini in a text editor like Notepad.
- Modify the MinClient build number to a value lower than the down-level build. For example, change 7100 to 7000.
- Save the file in place with the same name.
Run setup like you would normally from this modify copy of the image and the version check will be bypassed.
The RTM build of Windows 7 is distributed with the build number 7600. An upgrade from release candidate to RTM build would therefor require the modification of the MinClient build number from 7600 to 7100 or lower.