Pokémon GO’s Explorer Gadget has been updated to assist players while the game is open, letting Trainers level 20 and higher activate it to automatically attempt catches and spin PokéStops. A pink Poké Ball icon marks targets, which players can tap to take over within a limited time; the feature cannot run alongside a paired accessory. The update also adds a dedicated appraisal button and revises catch summaries, encounter indicators and several visual effects.
Source: Official Pokémon GO blog