Change the ASP.NET version in Plesk
To change the active ASP.NET version on your Plesk account, follow these steps:
1. Log in to Plesk.
2. In the left sidebar, click Websites & Domains.
3. Locate the domain you want to configure, and then click Hosting Settings:
4. Under Web Scripting and Statistics, in the Microsoft ASP.NET support (Version) list box, select the ASP.NET version you want to use: