In some cases, you build your ASP.NET 3.5 applications from scratch — starting everything new. In many instances, however, this is not an option. You need to take an ASP.NET application that was previously built on the 1.0, 1.1, or 2.0 versions of the .NET Framework and migrate the application so that it can run on the .NET Framework 3.5.
This appendix focuses on migrating ASP.NET 1.x or 2.0 applications to the 3.5 framework.
Be aware that Microsoft has done a lot of work to ensure that the migration process from ASP.NET 1.x is as painless as possible. In most cases, your applications run with no changes needed.
When moving a 1.x or 2.0 application to 3.5, you don't have to put the ASP.NET application on a new server or make any changes to your present server beyond installing the .NET Framework 3.5.
After you install the .NET Framework 3.5, you see the framework versions on your server at C:\WINDOWS\Microsoft.NET\Framework, as illustrated in Figure A-1.
In this case, you can see that all five official versions of the .NET Framework installed, including v1.0.3705, v1.1.4322, v2.0.50727, v3.0, and v3.5.
Figure A.1. Figure A-1
From this figure, you can see that it is possible to run multiple versions of the .NET Framework side by side. ASP.NET 1.0, ASP.NET 1.1, ASP.NET ...