Dalaran moves to the Broken Isles as the mages of the Kirin Tor want to keep close to the events of the Burning Legion's third invasion from the Tomb of Sargeras, the fallen Titan and ravager of Worlds.
The floating city receives several upgrades and can be found floating in the southern Broken Isles, south of Suramar and southeast of Azsuna.
The center of the city is now taken up by the Chamber of the Guardian. Inside is a central teleportation pad that leads to the Aegwynn's Gallery, the lower level of which houses portals to some notable areas: Caverns of Time, Shattrath, Wyrmrest Temple, Dalaran Crater (actually above; be prepared to fall), and Karazhan. These are in place for ease of travel for players securing their artifact weapons.