What ad system are you building ads for and where did you see a reference to this?
My recollection is that you can’t use exit APIs for certain systems anymore. Instead your entire ad will just be clickable and you don’t need to do anything (other than define the exit in the ad system yourself).
If you’re building ads with export scripts I think they all work for the intended platform, but say if you’re using the doubleclick studio export script to make an adwords ad, it won’t work because of this change. I’d need to double check though, depending on your response to the first question!