Display Condition: Show until X date (Pro)
If you have a limited time sale or only want the popup to show for a time, then you can use this and it will automatically stop showing the popup after a certain date.
When editing your popup, you want to click the Display Conditions
When you click on that, there will be another popup, at the very bottom of is Show until X date, which you can turn on and select the date you want.
After you have entered the date, you can click the x button (at the top-right) then the save / publish the popup.