Either form of spelling is still acceptable and in usage, but French spelling reforms have made the circonflexe optional in many words including the -aitre (-âitre) verbs- the more modern form of spelling is without it. Unfortunately in the dictations it appears that only 1 'best' answer is available, and others are subject to correction, even if they appear on the list of alternative answers. (At least, I have seen this on occasions)

I checked the spelling out in the Bible aka “Bescherelle, La conjugaison pour tous” and it quotes “apparaîtront”. 

Bescherelle en ligne presents both, orthographe 'traditionnelle' and orthographe 'rectifiée'. The circonflexe is optional in most now situations but not all - for instance it is retained in passé simple in 'nous' and 'vous' forms.