This topic demonstrates how to run an ASP.NET version 1.x Web application in the .NET Framework version 2.0. As a prerequisite, the ASP.NET 1.x Web application should be able to run in the .NET Framework 1.x version with which it was developed.

The .NET Framework allows you to install multiple versions of the common language runtime on the same computer. Installing the .NET Framework 2.0 will not disrupt any existing applications that are running on previous versions of the .NET Framework. The .NET Framework 2.0 is designed to have a high degree of backward compatibility with applications built with previous versions of the .NET Framework. An application running on a previous version of the .NET Framework can be made to run on the .NET Framework 2.0 by mapping the application to use the ASP.NET 2.0 ISAPI extension (Aspnet_isapi.dll). For more information on running multiple versions of the .NET Framework side by side, see ASP.NET Side-by-Side Overview.

Running an ASP.NET 1.x application in the .NET Framework 2.0 allows you to use ASP.NET 2.0 features in your application's pages. If you choose to migrate your application, you should review what's new in ASP.NET, and in particular review changes to the page code-behind model, Web site folder structure, and dynamic page compilation. For more information on migrating from ASP.NET 1.x to ASP.NET 2.0, see Migrating ASP.NET 1.x Applications to ASP.NET 2.0.