It is time to move onto Unicode. The multi-byte character set (MBCS) in MFC will not be supported in the future versions of Visual Studio. You can still compile the MBCS projects with VS2013, but you need to install the MBCS libraries via a separate download, which is available here. You will see a deprecation warning, when an application is built using MBCS, though. This warning can be suppressed by adding the NO_WARN_MBCS_MFC_DEPRECATION preprocessor definition.
For more information, see http://blogs.msdn.com/b/vcblog/archive/2013/07/08/mfc-support-for-mbcs-deprecated-in-visual-studio-2013.aspx.