That is false. They did not remove any code to make it not run on XP. They made additions to the CRT which made use of Vista+ APIs and thus the CRT would not be able to run on XP. They are now going to rewrite the parts that relied on the Vista+ APIs so the CRT (and thus C++ programs that rely on it) will run on XP.
Please give me the supporting info (e.g. changes in CRT VS 2012 versus the one in VS 2010). What I have is the same story but related to Windows 2000 support in previous compilers, and I doubt there's any difference: at the moment they removed support Windows 2000 for those who bought expensive new Visual Studios, they in fact had the proper support properly implemented and used. The proof was that it was even delivered in WDK which used the same new compiler backends:
Up to now removal of support of earlier versions of Windows was never caused by technical limitations but only by "political" decisions. If you have different specific examples please provide them.
