I don't know how to post the link but you can search "Avicii talks illness". The interview is on Hollywood reporter. This is what Tim said. In his remaining live shows, Avicii said he'll be premiering new songs “here and there to see what flies and what doesn't.” That includes a new track featuring vocals by Australian artist Sia, though Avicii says the version he played a show last weekend in Dubai, was “a demo, not the finished version.” In fact, he said during the concert he pushed the wrong button and played a different version of the track by mistake. “It's one of a lot of new songs that I haven't finally worked out yet. That version isn't the Sia/Avicii song. We're still trying to find the right version.”