Andres Muschietti announced shortly after the first movie that although IT 2 takes place nearly 30 years after the events of the first film, that the young cast will return through flashbacks.
Instead, it looks like IT 2 production will begin in July with the working title of Largo.
IT 2, aka IT Chapter 2, was announced shortly after the release of the first movie and had been the plan all along.
Andres Muschietti has been teasing the production start for a few months on social media.