The Trump administration has begun revoking the legal status of migrants who entered the U.S. under a Biden administration process powered by a smartphone app formerly known as CBP One, instructing them to leave the country immediately or face arrest and deportation.

The Department of Homeland Security (DHS) has ordered migrants who entered the U.S. via the CBP One app to leave "immediately."The Biden-era CBP One app—through which more than 900,000 people were allowed temporary entry beginning in January 2023—was used to schedule appointments at ports of entry and helped migrants live and work under parole in the U.