Over 500 million Pokemon have been caught in Pokemon GO’s Global Catch Challenge, Niantic says.
As such, the Bronze rewards tier has been unlocked for all trainers worldwide. This means the experience trainers gain has been doubled, Lure modules now last for 6 hours, and the spawn rate of Pokemon has increased.
— Pokémon GO (@PokemonGoApp) November 21, 2017
The next reward tier will be unlocked once 1.5 billion Pokemon have been captured worldwide. View the reward tiers here.