Yes, it seems to be true. A new album is scheduled for release on June 6th, but a new single named S.O.S. will be released this week.
Apparently Avicii left songs that were almost finished when he died. They are being finished now.
The New York Times has a good article about Avicii, his legacy and also his parents. Read it if you are a fan. Here is an excerpt of the interview with Avicii's (Tim Bergling) father, Klas Bergling.
He described his son as very shy growing up, a deep thinker who felt comfortable socially only with his closest friends. They spent countless hours in this apartment playing video games and watching the “The Lord of the Rings” film series and “Twin Peaks: Fire Walk With Me.” Music came to him later, as a midteen, after his blues-loving, guitar-playing father gave him a guitar of his own. “Tim advanced quickly from my quality,” Bergling said with a smile.