I heard somewhere that it was to replace the propulsion system. It has also been a while since the ship was launched so it probably will be spruced up.
I heard also heard that they were getting rid of Notes. I am not sure if Cirque will be put on as it is being removed from the Summit. We're just going to have to wait and see.
One thing I am glad about is that our TA was able to secure us great one way fares to Barcelona through Celebrity. At least that way, if the drydock takes longer than expected, we won't be out any money as we can cancel our hotel up until 24 hours before. We are spending a few days in Ft. Myers post cruise, so we booked our own airfare from Ft Myers home to Chicago via USA 3000. For Celebrity to do custom air from there home, it would have been at list prices as that is not one of their hubs.