Q. How do I upgrade the Windows 7 or Windows Server 2008 R2 OS SKU in a VHD to a higher version?

A. If you've used the method discussed in the previous FAQ on a mounted VHD and ascertained that it can be set to a higher version, use the /set-edition: switch to upgrade the VHD to a higher version of the OS. In the example below, I change from Home Basic to Ultimate.

D:DocumentsScripts>dism /image:w: /get-targeteditions

 Deployment Image Servicing and Management tool
 Version: 6.1.7600.16385

 Image Version: 6.1.7600.16385

 Editions that can be upgraded to:

 Target Edition : Ultimate
 Target Edition : Professional

 The operation completed successfully.

 D:DocumentsScripts>dism /image:w: /set-edition:Ultimate

 Deployment Image Servicing and Management tool
 Version: 6.1.7600.16385

 Image Version: 6.1.7600.16385

 Pended operations ignored. When this image is next booted, these operations will
 be processed.
 Starting to update components...
 Removing package Microsoft-Windows-ProfessionalEdition~31bf3856ad364e35~amd64~~6
 .1.7600.16385
 \[=====================

100.0%

=====================\]
 Finished updating components.

 Starting to apply edition-specific settings...
 Finished applying edition-specific settings.

 The operation completed successfully.

 D:DocumentsScripts>dism /image:w: /get-currentedition

 Deployment Image Servicing and Management tool
 Version: 6.1.7600.16385

 Image Version: 6.1.7600.16385

 Current edition is:

 Current Edition : Ultimate

 The operation completed successfully.

You can't downgrade to a lower version—for example, you can't go from Ultimate down to Home Premium. Note that if you upgrade a Server OS, you also need to pass the new SKU product key using the /ProductKey: switch.

If you want to pass an unattended answer file into your image, just use the /Apply-Unattend: switch.