diff --git a/libguac/include/protocol.h b/libguac/include/protocol.h
index e59167f1..78999b5e 100644
--- a/libguac/include/protocol.h
+++ b/libguac/include/protocol.h
@@ -145,22 +145,26 @@ void guac_send_size(GUACIO* io, int w, int h);
  * Sends a copy instruction over the given GUACIO connection.
  *
  * @param io The GUACIO connection to use.
+ * @param srcl The index of the source layer.
  * @param srcx The X coordinate of the source rectangle.
  * @param srcy The Y coordinate of the source rectangle.
  * @param w The width of the source rectangle.
  * @param h The height of the source rectangle.
+ * @param dstl The index of the destination layer.
  * @param dstx The X coordinate of the destination, where the source rectangle
  *             should be copied.
  * @param dsty The Y coordinate of the destination, where the source rectangle
  *             should be copied.
  */
-void guac_send_copy(GUACIO* io, int srcx, int srcy, int w, int h, int dstx, int dsty);
+void guac_send_copy(GUACIO* io, int srcl, int srcx, int srcy, int w, int h,
+        int dstl, int dstx, int dsty);
 
 /**
  * Sends a png instruction over the given GUACIO connection. The PNG image data
  * given will be automatically base64-encoded for transmission.
  *
  * @param io The GUACIO connection to use.
+ * @param layer The index of the destination layer.
  * @param x The destination X coordinate.
  * @param y The destination Y coordinate.
  * @param png_rows A libpng-compatible PNG image buffer containing the image
@@ -168,21 +172,23 @@ void guac_send_copy(GUACIO* io, int srcx, int srcy, int w, int h, int dstx, int
  * @param w The width of the image in the image buffer.
  * @param h The height of the image in the image buffer.
  */
-void guac_send_png(GUACIO* io, int x, int y, png_byte** png_rows, int w, int h);
+void guac_send_png(GUACIO* io, int layer, int x, int y,
+        png_byte** png_rows, int w, int h);
 
 /**
  * Sends a cursor instruction over the given GUACIO connection. The PNG image
  * data given will be automatically base64-encoded for transmission.
  *
  * @param io The GUACIO connection to use.
- * @param x The destination X coordinate.
- * @param y The destination Y coordinate.
+ * @param x The X coordinate of the cursor hotspot.
+ * @param y The Y coordinate of the cursor hotspot.
  * @param png_rows A libpng-compatible PNG image buffer containing the image
  *                 data to send.
  * @param w The width of the image in the image buffer.
  * @param h The height of the image in the image buffer.
  */
-void guac_send_cursor(GUACIO* io, int x, int y, png_byte** png_rows, int w, int h);
+void guac_send_cursor(GUACIO* io, int x, int y,
+        png_byte** png_rows, int w, int h);
 
 /**
  * Returns whether new instruction data is available on the given GUACIO
diff --git a/libguac/src/protocol.c b/libguac/src/protocol.c
index 4d3110e6..5a37e403 100644
--- a/libguac/src/protocol.c
+++ b/libguac/src/protocol.c
@@ -199,8 +199,10 @@ void guac_send_error(GUACIO* io, const char* error) {
 
 }
 
-void guac_send_copy(GUACIO* io, int srcx, int srcy, int w, int h, int dstx, int dsty) {
+void guac_send_copy(GUACIO* io, int srcl, int srcx, int srcy, int w, int h, int dstl, int dstx, int dsty) {
     guac_write_string(io, "copy:");
+    guac_write_int(io, srcl);
+    guac_write_string(io, ",");
     guac_write_int(io, srcx);
     guac_write_string(io, ",");
     guac_write_int(io, srcy);
@@ -209,6 +211,8 @@ void guac_send_copy(GUACIO* io, int srcx, int srcy, int w, int h, int dstx, int
     guac_write_string(io, ",");
     guac_write_int(io, h);
     guac_write_string(io, ",");
+    guac_write_int(io, dstl);
+    guac_write_string(io, ",");
     guac_write_int(io, dstx);
     guac_write_string(io, ",");
     guac_write_int(io, dsty);
@@ -228,7 +232,7 @@ void __guac_write_png(png_structp png, png_bytep data, png_size_t length) {
 void __guac_write_flush(png_structp png) {
 }
 
-void guac_send_png(GUACIO* io, int x, int y, png_byte** png_rows, int w, int h) {
+void guac_send_png(GUACIO* io, int layer, int x, int y, png_byte** png_rows, int w, int h) {
 
     png_structp png;
     png_infop png_info;
@@ -272,6 +276,8 @@ void guac_send_png(GUACIO* io, int x, int y, png_byte** png_rows, int w, int h)
     );
     
     guac_write_string(io, "png:");
+    guac_write_int(io, layer);
+    guac_write_string(io, ",");
     guac_write_int(io, x);
     guac_write_string(io, ",");
     guac_write_int(io, y);