I have tried to import playlist from Traktor PRO 3 to Traktor DJ2, the app couldn't recognise the exported file.
In addition, Traktor DJ2 doesn't recognise the music I have on my USB so I can't play a song even I connect my S2 MK2 to my iPad.
I am a bit confused because of this problem, I think the app should be improved to import songs from a USD or any other external device. For me, Traktor DJ2 is useless nowadays.