Ghostbusters IV

Plot
Ten years after, Ghostbusters III, Egon, Peter, Ray, and Winston have announced that they'll retire in one week.

But, Eddie Spencer Jr. Jake Kong Jr,, and Tracy The Gorilla, Eric Smith, Spike, and Ziggie still have plenty of fight left in them and potential of Ghostbusters, so on the original four busters final weeks they train the new team to be good busters.

And eventually Ghosts from other planet come to Earth to rule among so its up to  The Old and The New to stop Alien Ghosts.

Reboot
The Extreme Ghostbusters