Alexandre Desplat has been named the composer of Rogue One, making the first stand-alone Star Wars movie the first to also be made without the help of John Williams. I feel pretty confident, however, that even if Williams doesn't personally work on the film, many of his iconic Star Wars themes will.
To be fair, Desplat is no slouch in the musical scoring department, having worked on The Imitation Game, Godzilla, Argo, Zero Dark Thirty, Harry Potter and the Deathly Hallows and recently winning an Academy Award for The Grand Budapest Hotel. And Williams is already signed to do the music for Episodes VII, VIII and IX, so we still have plenty of more Star Wars tunes from him to come.
[Via The AV Club]