We will likely not getting any more in the immediate future, at least until the female pictured here (Ybonga) passes away. She is nearing 40, her lifetime mate (Zibulu) passed away a couple years ago, and there is little point in trying to do a new introduction near the end of her life.
Once she passes, anything could happen. One idea that is floating around from the newly adopted master plan, is to convert the zebra and ostrich and crown crane yard north of this into an Asian exhibit and put in an indian rhino. Then move those animals over to this yard. But as I said, anything could happen.