I am not sure. I can tell you that I had a nine spead ultegra and I broke the rear deraileur so I replaced it with a 10 speed. It was compatiable. Now I upgraded the system to 10 speed which included the cassettes, chain, shifters, and of course the deraileur that I already had. I change out the cranks also because they were worn out. I did not change out the front deraileur that has nothing to do with it. It was a double but since you have a triple it should not have any thing to do with the rear drive train at all. I am not sure about your situation, but it seems that it would not matter what you change on the rear, it should not have anything to do with the front. Hope this helps.
