diff --git a/include/boost/config/compiler/visualc.hpp b/include/boost/config/compiler/visualc.hpp
index df61d4b6..5ff72297 100644
--- a/include/boost/config/compiler/visualc.hpp
+++ b/include/boost/config/compiler/visualc.hpp
@@ -43,7 +43,7 @@
 #  error "Compiler not supported or configured - please reconfigure"
 #endif
 
-#if _MSC_VER < 1800
+#if _MSC_FULL_VER < 180020827
 #  define BOOST_NO_FENV_H
 #endif
 
@@ -170,7 +170,7 @@
 
 // C++11 features supported by VC++ 12 (aka 2013).
 //
-#if _MSC_VER < 1800
+#if _MSC_FULL_VER < 180020827
 #  define BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
 #  define BOOST_NO_CXX11_DELETED_FUNCTIONS
 #  define BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
@@ -179,9 +179,13 @@
 #  define BOOST_NO_CXX11_TEMPLATE_ALIASES
 #  define BOOST_NO_CXX11_TRAILING_RESULT_TYPES
 #  define BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
-#  define BOOST_NO_CXX11_VARIADIC_TEMPLATES
 #endif
 
+// variadic templates are supposed to be supported by VC++ 12
+// but VC++ 12 RC variadic support is causing boost regression
+// test failures for signals2 and several of its dependencies.
+#define BOOST_NO_CXX11_VARIADIC_TEMPLATES
+
 // C++11 features not supported by any versions
 #define BOOST_NO_CXX11_CHAR16_T
 #define BOOST_NO_CXX11_CHAR32_T