Pokémon GO update version 0.421.0 is now rolling out to iOS and Android devices, bringing the latest client required for upcoming in-game events and feature support as the game’s 10th anniversary celebration continues. As with previous app releases, the update is expected to become available gradually through the App Store and Google Play, meaning some Trainers may receive it before others depending on their region and platform. Players are encouraged to install version 0.421.0 once it becomes available to ensure compatibility with the latest Pokémon GO content, events and gameplay updates.
Source: Official Pokémon GO support
Source: Pokemon
