I got the same note this morning. I asked for more information about the change and what would be involved to convert a plane that was already built. Here's the response.
It looks like same as you have. The different is material on the shaft. We changed it to be aluminum with fiberglass inside the holes. It becomes very strong than before. It is very simple to convert to the new elevators.
There aren't too many of these flying yet and if there were any failures it probably would have been posted on RCU. I don't see any reason why the carbon fiber shafts wouldn't be strong enough. Unless there is a known defect I don't think it's worth $50 to upgrade, unless you plan on flying a lot of 3D.
Joe