Remove Windows version information

It has been out of date for some time.
diff --git a/README.txt b/README.txt
index 0c3c534..de346a1 100644
--- a/README.txt
+++ b/README.txt
@@ -64,9 +64,8 @@
   winvnc - the TigerVNC Server for Windows.  winvnc allows a Windows desktop to
            be accessed remotely using a VNC viewer.
 
-The Windows version of TigerVNC should work on Windows 2000 and later.  On
-Windows XP and later, winvnc may not work if the Fast User Switching or Remote
-Desktop features are in use.
+winvnc may not work if the Fast User Switching or Remote Desktop features are
+in use.
 
 
 Unix/Linux-Specific (not Mac)