Mapbox maps require the use of Mapsbox’s own mapping engine, which conflicts with the mapping engine that our plugin is based on (Leaflet). On top of that, the new Mapbox maps are vector maps, whereas Maps Marker Pro uses raster maps. We therefore don’t have any plans to support the new Mapbox Studio maps at this time. You can continue to use the classic styles for as long as Mapbox provides them, even in Version 4, by adding them as a custom layer.