CoroCoro is slowly leaking out! In this image they have announced that in the next issue (out on October 15, 2014) will be given a serial code to download a demo version of Omega Ruby or Alpha Sapphire. Players will be able to use Grovyle, Combusken, or Marshtomp in the demo. No more details are given at the moment. Source: serebii EDIT: the page also says that the demo will end when you obtain a Mega Evolution.