Several evolutionary levels of Poké mon Haunter

Poké mon Haunter evolved at level 25. By querying Pokémon letsgo's game strategy, it shows that the evolution of Haunter needs the automatic evolution when the level of Gastly reaches 25, while the evolution of Haunter needs the communication between players. After the communication exchange is completed, Haunter will automatically evolve into Gengar, with no other restrictions. At this time, Gengar can take it back. Therefore, Poké mon Haunter evolved at level 25.