Now Gengar use Sludge Bomb instead of Sludge Wave. For the details of the update, tap the link below.
Pokemon got their moves changed or removed | PokemonGo
What is DPS and EPS in Pokemon Go?
Best Pokemon for fighting against Exeggutor
Suicune stats & moveset
Best Pokemon to defeat Gyarados
Dratini nests and spawn locations
Best Pokemon to beat Dragonite