Boxing & unboxing is the process of converting a primitive value into an object oriented wrapper class (boxing), or converting a value from an object oriented wrapper class back to the primitive value (unboxing).
The Old Dalaran will stay in Northrend, so yes, mages are going to have 2 portals to dalaran (one to Northrend and one to the Broken Isles)
The expansion will also feature a new continent called âThe Broken Isles.â Dalaran will be returning as the main hub (again, a lot like Wrath of the Lich King). Players will start out however at the fabled âTomb of Sargerasâ from Warcraft lore. Itâs pure speculation at this point, but it could be that Sargeras himself (one of the most feared adversaries in the lore) will finally be appearing in World of Warcraft.