The app for tracking and tracing coronavirus in Northern Ireland has been released for download from Apple’s App Store and on Google Play.
Named StopCOVID NI, it has several features for logging details of those experiencing symptoms of the virus.
It will supplement the phone-based contact tracing programme already in place and will identify those at risk of infection.
Northern Ireland is the first part of the UK to have a contact tracing app.
StopCovidNI will be officially launched on Friday but became available to download on Thursday afternoon.
Within an hour of its release, hundreds of people had installed it on their mobile phones.
How does it work?
After a positive Covid-19 test result, a person will receive a unique code by text message.
That message will invite the person to enter the code if they use the app.
Entering the code will trigger a “Bluetooth handshake”, allowing the app to notify any other user who has been nearby for long enough to be at risk of infection.
“There will be some people who won’t be able to or won’t want to use the app, and that’s okay,” said Dan West, the chief digital information officer at the Department of Health.
“The more people who do use it, the more protection this will provide to the whole community. We can say that for sure.”
The app will be intended for over-18s initially, because of a conflict between data protection laws and the need for identifiable safeguarding consent.
Dr Eddie O’Neill from the Health and Social Care Board is meeting the children’s commissioner, the information commissioner’s office and the Children’s Law Centre to find a way through that.
Will it work alongside the Republic’s app?
Health Minister Robin Swann previously said his department was working with its counterpart in the Republic of Ireland.
The ambition was to have the two systems work in tandem, so information about contacts who need to be traced can be shared by both governments.
Both apps have been designed by the same company, Nearform.
The contact tracing programme has been operational in Northern Ireland since mid-May.
It involves people with a positive test result being contacted by phone.
The people they have been within 2m of for 15 minutes or more are called and advised about isolating or being tested if they have symptoms.
The app is an add-on to that, to help with contact tracing, and alert those who may not be easily contacted.