Michael Giacchino has replaced Alexandre Desplat as the composer for Rogue One, The Hollywood Reporter says today. The switch is due to scheduling issues stemming from the recent reshoots.
Giacchino has quite a long resume, including all three of the new Star Treks, several Pixar films (including The Incredibles and Up, which he won an Oscar for) and the upcoming Doctor Strange.
Upgrade in my opinion. He can do war style scores great considering he did tthem for the Medal Honor and Call of Duty video game series also.