diff --git a/builds/cmake/platform.hpp.in b/builds/cmake/platform.hpp.in
index b1039dea..21930c42 100644
--- a/builds/cmake/platform.hpp.in
+++ b/builds/cmake/platform.hpp.in
@@ -86,14 +86,4 @@
 
 #cmakedefine ZMQ_HAVE_WINDOWS
 
-#ifdef ZMQ_HAVE_WINDOWS
-  #if defined _WIN32_WINNT && _WIN32_WINNT < 0x0600
-    #undef _WIN32_WINNT	
-  #endif
-
-  #ifndef _WIN32_WINNT 
-    #define _WIN32_WINNT 0x0600
-  #endif
-#endif
-
 #endif
\ No newline at end of file
diff --git a/builds/mingw32/platform.hpp b/builds/mingw32/platform.hpp
index 62d36c1f..4af872cd 100644
--- a/builds/mingw32/platform.hpp
+++ b/builds/mingw32/platform.hpp
@@ -29,13 +29,4 @@
 
 #define ZMQ_HAVE_WINDOWS
 
-#if defined _WIN32_WINNT && _WIN32_WINNT < 0x0600
-  #undef _WIN32_WINNT	
-#endif
-
-#ifndef _WIN32_WINNT 
-  #define _WIN32_WINNT 0x0600
-#endif
-
-
 #endif
diff --git a/builds/msvc/platform.hpp b/builds/msvc/platform.hpp
index d6e0ce60..4af872cd 100644
--- a/builds/msvc/platform.hpp
+++ b/builds/msvc/platform.hpp
@@ -29,12 +29,4 @@
 
 #define ZMQ_HAVE_WINDOWS
 
-#if defined _WIN32_WINNT && _WIN32_WINNT < 0x0600
-  #undef _WIN32_WINNT	
-#endif
-
-#ifndef _WIN32_WINNT 
-  #define _WIN32_WINNT 0x0600
-#endif
-
 #endif
diff --git a/src/condition_variable.hpp b/src/condition_variable.hpp
index e6c6c52b..fbcad36a 100644
--- a/src/condition_variable.hpp
+++ b/src/condition_variable.hpp
@@ -31,6 +31,47 @@
 
 #include "windows.hpp"
 
+// Condition variable is supported from Windows Vista only, to use condition variable define _WIN32_WINNT to 0x0600
+#if _WIN32_WINNT < 0x0600
+
+namespace zmq
+{
+
+	class condition_variable_t
+	{
+	public:
+		inline condition_variable_t ()
+		{
+			zmq_assert(false);
+		}
+
+		inline ~condition_variable_t ()
+		{
+
+		}
+
+		inline int wait (mutex_t* mutex_, int timeout_ )
+		{
+			zmq_assert(false);
+			return -1;
+		}
+
+		inline void broadcast ()
+		{
+			zmq_assert(false);
+		}
+
+	private:		
+
+		//  Disable copy construction and assignment.
+		condition_variable_t (const condition_variable_t&);
+		void operator = (const condition_variable_t&);
+	};
+
+}
+
+#else
+
 namespace zmq
 {
 
@@ -79,6 +120,8 @@ namespace zmq
 
 }
 
+#endif
+
 #else
 
 #include <pthread.h>
diff --git a/src/windows.hpp b/src/windows.hpp
index eeb05fd1..39a52698 100644
--- a/src/windows.hpp
+++ b/src/windows.hpp
@@ -27,9 +27,9 @@
 #define NOMINMAX          // Macros min(a,b) and max(a,b)
 #endif
 
-//  Set target version to Windows Server 2003, Windows XP/SP1 or higher.
+//  Set target version to Windows Server 2008, Windows Vista or higher. Windows XP (0x0501) is also supported but without client & server socket types.
 #ifndef _WIN32_WINNT
-#define _WIN32_WINNT 0x0501
+#define _WIN32_WINNT 0x0600
 #endif
 
 #ifdef __MINGW32__