In every major release like Visual Studio 2005 and the .NET Framework 2.0, we spend a lot of effort ensuring application compatibility with previous versions.  We do a lot of testing and internal reviews to ensure that your applications continue to work smoothly when you install the next version of the Framework.  We know that many of you have built very compelling applications using Visual Studio .NET 2003 and the .NET Framework 1.1 and we want you to be able to take advantage of the new functionality that is coming with the next release.

Today we’ve released a series of whitepapers that contain more information on our compatibility efforts, the list of breaking changes, and information on how to test your applications.  Jason Zander, the Product Unit Manager for the CLR has also blogged about the project upgrade experience.  Though the team has provided an exhaustive listing of all the changes that might potentially impact an application, only a small number (subset) of the changes that are listed have ever been seen to actually impact an application.

So what should you be doing with this information?  The first step is to go test your application – we’ve provided detailed testing instructions that walk through the same steps that we use when testing applications with customers.  We’ve done a lot of testing in house.  I am sure there are other applications that we haven’t seen, so let us know if you find anything else that impacts your application.  The purpose of the beta releases is so that we can address or document any changes before we release Visual Studio 2005. 

Secondly, we’re still looking for more applications that we can bring in house for testing purposes.  If you have an application that you think would be interesting, please see the information on how to submit that application or see Jay Roxe’s blog and somebody here will get back to you.  We already have hundreds of applications that we’re using but are always looking to add more. 

Many people will ask what we’re going to do with these results and whether there’s even time left in the Whidbey product cycle to take advantage of them.  The answer is that there is absolutely time to make sure that we address any compatibility issues that are discovered.  We are going to look at each of the results that we find and either fix the compatibility issue or as appropriate, ensure that we’ve documented the change with information on how to make your application work smoothly.

eWeek this morning posted a story about our compatibility efforts.  I encourage people to read beyond the headline (“Microsoft .NET Framework 2.0 Breaks Apps”) because we're doing tons to help customers avoid breaking apps.  The text of the article is spot on about the efforts that we’re doing to find and test applications.  They also talked with Infragistics, a partner with over 1.8 million lines of code, who has been very happy with the work that we’ve done in the .NET Framework 2.0.

I would love to hear from you on your experience testing your applications with .NET Framework 2.0 and any other ideas that you may have on what we should be doing here. 

Namaste!