Within weeks of Covid-19 shutting down the world in 2020, teams at archrivals Apple and Google partnered on a rare joint project. )States giving up on exposure notifications are able to send mobile push notifications to users informing them that the system is being shut down, and that users can delete their state app or turn off the service in their smartphone settings, depending on how it is set up on their devices. It could provide exposure notifications during flu season or help parents track immunization schedules for children