Application Compatibility and .NET 2.0 - Kirk Evans Blog - Site Home

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:

Channel9 video explaining application compatibility. Jesse Kaplan -- Will your .NET 1.1 apps work on 2.0 or vice versa?
A list of steps that show you how to test for application compatibility. Compatibility Testing Scenarios
Understand how multiple versions of the framework run side by side. Side-by-side Execution of the .NET Framework
Understand the load behavior, mitigating possible compatibility issues, and potential hotspots for application compatibility. Even though it references the beta, this information is still relevant to RTM. Microsoft .NET Framework 1.1 and 2.0 (Beta) Compatibility
A list of the breaking changes from previous versions of the .NET Framework to .NET 2.0. Breaking changes in .NET 2.0 framework

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.