John Mayer has finally released a new single and it's about his old flame, Jennifer Aniston. John and Jen dated off and on from 2008 to 2009. After they broke up John "secretly" dated Taylor Swift before completely disappearing from the media. Well, now John is back with a single titled "Shadow Days" and it's supposedly about his relationship with Jennifer! In the song, John sings about the breakup and how everything will one day be all right. Is this John's comeback? We've missed him, but the Jen-thing is a bit old!