If you’re an early Visual Studio adopter like me you’ve probably gotten used to running into a similar problem every few years: upgrading your code. Although VS usually handles the job of converting files to work in the newer version, the big problem has usually been trying to go back to the old version. If you’re the only one working with the code that might not matter, but if you work on a team that has a mix of, for example, VS 2008 and VS 2010 Beta clients, the conversion process causes problems for one or the other.
Finally in VS 11 this problem is being addressed. The ultimate goal is to be able to open a VS 2010 solution in VS 11 with minimal conversion and applying no breaking changes to the project or solution files that would prevent it from still opening directly in 2010. There will of course be some restrictions, like not upgrading to .NET 4.5, but in general seems like a pretty reasonable goal.
To see how it’s working so far with the Developer Preview I tried upgrading a few of my own projects, including a 50+ project solution with lots of complications. The good news was that the upgrade process did succeed without preventing VS 2010 from opening the converted solutions that I tried. There were, however, some issues.