I have a friend that has an issue using my asp.net C# custom control in Visual Studio.net 2002 that I have compiled under Visual Studio.net 2003. I never did test it with that version, but I was under the impression that it should still work as long as you don't use any features specific to the 1.1 framework (which I really don't think I did). My guess now is that this is correct, but only when using 2002 controls in 2003. I have searched the web, these forums, and MSDN for the last 30 minutes with no real answer. The guy that runs MetaBuilders (http://www.metabuilders.com/Faq.aspx) tells people to recompile his controls with vs.net 2002. I'm hoping there is a better answer because I'd hate to maintain separate builds of my control. Can someone else shed some light on this topic?