It was announced via the Fate/kaleid liner Prisma☆Illya Movie: Sekka no Chikai Machi Asobi Vol.19 event on Saturday that a sequel for the franchise is in production.
Fate/kaleid liner Prisma☆Illya is based on the manga written and illustrated by Hiroshi Hiroyama.
The series was first adapted to a TV anime in July 2013, with a new season premiering for four consecutive summers since, each produced by Silver Link.
More information will be announced at a later date.