http://www.newsweek.com/pokemon-go-halloween-2018-update-1184201

After details for the Pokémon Go Halloween event were leaked, Niantic has announced the Halloween event update coming to  includes more Gen 4 Pokémon than previously thought.

The in-game message began popping up in Pokémon Go alerting trainers to what they can expect in the coming weeks If you’re looking to get the most out of the Halloween 2018 event, here’s the start time, and all the new Pokémon coming to Pokémon Go.