The official Pokémon movie blog has updated. Translations of the new entry follows:
Appear! Movie Details #2: "Désser City" Concept Art Appears!
Désser City (Distant View)Désser City (Distant View/Night)
Désser City is a city located in the middle of a desert that serves as the story's setting!!
This is where Satoshi, Pikachu and Hoopa's grand adventure will unfold!
Source:
http://www.pokemon-movie.jp/pokemovie_ch/?p=273