Please follow the below steps to change the ASP.NET Framework version,
- Log in to your Control Panel.
- Under My Subscriptions click the subscription you want to manage.
- Click the Websites & Domains tab and click Show More at the bottom of the page.
- Click ASP.NET Settings.
- Click Change Version.
- Select the version you wish to change to then click OK.
Notes:
When choosing your ASP.NET Framework through the control panel, you are actually choosing the CLR version (Common Language Runtime Version), This means that in order to use ASP.NET 3.5, you must select "Version 2" as ASP.NET 3.5 is an add-on for CLR 2.0. The same is true about ASP.NET 4.5 - selecting ASP.NET 4.0 actually loads the .NET 4.5 assemblies.