Pokémon GO update version 0.423.0 available now on iOS and Android

A new Pokémon GO update, version 0.423.0, is now available for download on iOS and Android devices, bringing the latest improvements and fixes for Trainers. The update arrives as Pokémon GO continues its summer events, including the Summer Marathon: Arctic Embers event featuring Shiny Snom’s debut, and the GO Pass: August season with Latias encounters and the return of the Lucky Trinket. Trainers can update through the App Store or Google Play to access the newest version of the mobile game.

Source: Official Pokémon GO support