The upgrade wizard is available only when there are references to Telerik assemblies in a project.
If there are no such references Convert Wizard is available instead of Upgrade wizard.
On the other hand the Convert Wizard is empty in your case because your web site is targeting .NET 2.0 but we do not support it any more.
So the correct approach when you are upgrading from one target framework to another is the following:
1. Change the target framework of the project/web site.
2. Start Upgrade Wizard if you already have Telerik references or start the Convert Wizard if you don't have Telerik references but you want to add them.
3. Also using the Upgrade/Convert wizards you could download the latest version of the assemblies using the Download button.
Our wizard will upgrade or add not only the right references to the project but they will also make all needed changes to the web.config files.
Here you could find some documentation for the VSExtensions: http://www.telerik.com/help/aspnet-ajax/introduction-vsx-overview.html.
Let me know if you need any further information.
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