Wpmu Dev Popup Pro is developed by WPMU DEV. You can download the version 4.8.1 for $5 or have it for free if you subscribe to a monthly plan.
Wpmu Dev Popup Pro is the SAME file as the original one (nulled version) developed by WPMU DEV. The last update of August 24, 2018 comes with new features and known bugs have been fixed.
For more information, click here to visit the developer page of this Wpmu Dev Popup Pro.