Installing Multiple Versions of the .NET Framework
You can install and run multiple versions of the .NET Framework on a computer. Currently there are two versions of the .NET Framework, version 1.0 and version 1.1. The two .NET Framework versions can be installed in any order.
You can also redistribute the .NET Framework with your application. For more information on including the .NET Framework with your application, see Redistributing the .NET Framework.
See Also
Using Side-by-Side Execution | Configuring Assembly Binding Redirection | Targeting a .NET Framework Version | Assembly Binding Redirection