diff --git a/common/rfb/SMsgWriter.cxx b/common/rfb/SMsgWriter.cxx
index bc3f439..d8adfbc 100644
--- a/common/rfb/SMsgWriter.cxx
+++ b/common/rfb/SMsgWriter.cxx
@@ -27,6 +27,7 @@
 #include <rfb/Encoder.h>
 #include <rfb/SMsgWriter.h>
 #include <rfb/LogWriter.h>
+#include <rfb/ledStates.h>
 
 using namespace rfb;
 
@@ -37,7 +38,8 @@
     nRectsInUpdate(0), nRectsInHeader(0),
     needSetDesktopSize(false), needExtendedDesktopSize(false),
     needSetDesktopName(false), needSetCursor(false),
-    needSetXCursor(false), needSetCursorWithAlpha(false)
+    needSetXCursor(false), needSetCursorWithAlpha(false),
+    needLEDState(false)
 {
 }
 
@@ -193,12 +195,26 @@
   return true;
 }
 
+bool SMsgWriter::writeLEDState()
+{
+  if (!cp->supportsLEDState)
+    return false;
+  if (cp->ledState() == ledUnknown)
+    return false;
+
+  needLEDState = true;
+
+  return true;
+}
+
 bool SMsgWriter::needFakeUpdate()
 {
   if (needSetDesktopName)
     return true;
   if (needSetCursor || needSetXCursor || needSetCursorWithAlpha)
     return true;
+  if (needLEDState)
+    return true;
   if (needNoDataUpdate())
     return true;
 
@@ -247,6 +263,8 @@
       nRects++;
     if (needSetCursorWithAlpha)
       nRects++;
+    if (needLEDState)
+      nRects++;
   }
 
   os->writeU16(nRects);
@@ -362,6 +380,11 @@
     writeSetDesktopNameRect(cp->name());
     needSetDesktopName = false;
   }
+
+  if (needLEDState) {
+    writeLEDStateRect(cp->ledState());
+    needLEDState = false;
+  }
 }
 
 void SMsgWriter::writeNoDataRects()
@@ -525,3 +548,20 @@
     data += 4;
   }
 }
+
+void SMsgWriter::writeLEDStateRect(rdr::U8 state)
+{
+  if (!cp->supportsLEDState)
+    throw Exception("Client does not support LED state updates");
+  if (cp->ledState() == ledUnknown)
+    throw Exception("Server does not support LED state updates");
+  if (++nRectsInUpdate > nRectsInHeader && nRectsInHeader)
+    throw Exception("SMsgWriter::writeLEDStateRect: nRects out of sync");
+
+  os->writeS16(0);
+  os->writeS16(0);
+  os->writeU16(0);
+  os->writeU16(0);
+  os->writeU32(pseudoEncodingLEDState);
+  os->writeU8(state);
+}