A new Pokémon GO update, version 0.417.6, is now rolling out for iOS and Android devices. As with many Pokémon GO updates, the official App Store listing does not include detailed patch notes and simply notes that the game is regularly updated with new events and features, directing players to the in-game News section for additional information. Version 0.417.6 is expected to include bug fixes, performance improvements and support for upcoming Pokémon GO content, although no additional changes have been officially announced at this time.
Source: Official Pokémon GO support
Nintendo & Pokémon Blog 