“Bono described the album as 'futuristic'. U2 going sci-fi or
something, that's how he described it.
"We've put down a few ideas, but we don't know how many will end up on there. They have a very special way of working. A song is never done until the day before it comes out almost, so you never know," Contactmusic quoted RedOne as saying.
Meanwhile, the music producer revealed that the new album will be guitar based with contributions from guitarist The Edge, bass player Adam Clayton and drummer Larry Mullen. “I'm a guitar player, so it was just me and Bono and Edge playing guitar, exchanging melodies. We were just like musicians jamming. I loved it," Billboard.com quoted RedOne as saying.