With app-based pet care services, such as DogVacay and Rover, becoming more popular, a regulation in New York City requiring anyone offering petsitting for a fee to be licensed to board animals is getting more attention as well. The city's Department of Mental Health and Hygiene oversees the regulation but notes that at-home dog-sitting businesses are not usually investigated unless a complaint is filed. The health department has issued letters to such app companies demanding that they cease operating illegally. The companies are fighting back and have been allowed to continue operating in some states.