Recent pictures of the movie that made it to retailers now confirms that Peanuts will be the first movie coming from the 20th Century Fox to features a Dolby Atmos soundtrack.
As stated by Fox before, this will be reserved only for the UltraHD Blu-ray edition on the movie, as not even the Blu-ray in the same box will offer Dolby Atmos.
As usual, I updated the list of Dolby Atmos Blu-rays movies on the site.