Well, since Beta 2 has been released I can let you know some stuff. Since I do not know everything that has changed I will just give you an overview. 1. Message routing/mapping has been changed. So, odds are if you do anything more than intercept WM_COMMAND messages it will probably break your code. Why they changed how the messaging system works is beyond me! 2. Some of the structures used within MFC have been changed. Some have had their members removed, other have had members added, and some even do not even exist anymore. So if you use any of these you will probably have a problem. I do not have a complete list yet, but I know there are a few. 3. If you use any of the "MFC internals", your code will probably need some recoding. So, if your program only uses the most common/basic MFC classes/functionality it will mostlikely work. Otherwise you are in for some code changes. For example ... about 35% of the classes in Ultimate Toolbox will require minor to major rewriting. However Ultimate Grid works perfectly with no changes. Hope this helps