What's happening to the old airport?. A lot of it is not that old.
It will continue to be used by GA traffic and Government operated aircraft/flights. I think that it also continues to be used by a number of cargo carriers. As for the terminal itself, I think I read there were rumours of some form of Exhibition & Conference Centre or a museum, or both, but no firm plans.
Just had a look at FR24 and I saw that, among others, THY Cargo flights continue to operate there.