Kirk Evans Blog

.NET From a Markup Perspective

Application Compatibility and .NET 2.0

Lots of customers who skipped the .NET 2.0 betas waiting for the RTM are now asking questions like, “will my application continue to run?” 

Some resources to help you understand application compatibility:

Something that lots of folks may not realize is that a computer with only .NET 2.0 runtime on it may still load a .NET 1.1 assembly.  The following table details the loading behavior of applications under different configurations of the .NET Framework.

Application type Computer with 1.1 Computer with 2.0 Computer with 1.1 and 2.0
1.1 stand-alone application (Web or Microsoft Windows client) Loads with 1.1 Loads with 2.0 Loads with 1.1
2.0 stand-alone application (Web or Microsoft Windows client) Fails Loads with 2.0 Loads with 2.0
1.1 add-in to a native application (such as Office or Internet Explorer) Loads with 1.1 Loads with 2.0 Loads with 2.0 unless the process is configured to run against 1.1
2.0 add-in to a native application (such as Office or Internet Explorer) Fails Loads with 2.0 Loads with 2.0

If you haven’t already, spend time going through these resources and testing your applications for .NET 2.0.  Then move on to .NET 2.0 and Visual Studio 2005 to enjoy better perf, increased security, and a slew of new productivity features.