England's long-delayed COVID-19 contacts-tracing app to launch on September 24

The U.K.'s long-delayed coronavirus contact-tracing app finally has a release date: The Department of Health and Social Care (DHSC) announced today that the app will launch in England and Wales on September 24.

The other regions of the country, Scotland and Northern Ireland, already have their own COVID-19 contacts-tracing apps -- the latter launching an app this summer. The Protect Scotland app was released yesterday, where it went on to clock up more than 600,000 downloads in a matter of hours.

England and Wales have had a far lengthier-than-expected wait for an app after a false start back in May, when government ministers had suggested in daily coronavirus briefings that an app would be landing shortly.

Instead, the launch was delayed, and DHSC took over development of the NHS COVID-19 app from the National Health Service's digital division, NHSX, after it ran into problems related to the choice of a centralized app architecture -- which triggered privacy concerns and saw the test app plagued by technical issues around iPhones' device detection.

The government pivoted the app to a decentralized architecture, which means it's able to make use of exposure notification APIs offered by Apple and Google for official COVID-19 contacts-tracing apps, avoiding the technical issues associated with iOS background Bluetooth detection.

Another element that's been added to the NHS COVID-19 app is a check-in feature for venues via scannable QR codes. The government is encouraging businesses and locations where people may congregate, such as pubs, restaurants, hairdressers, libraries and so on, to print out and display a QR code that app users can scan to check into the venue.

This check-in data will be held locally on the device, taking the same privacy-preserving approach as for contacts data generated when devices come into proximity and swap ephemeral IDs.

Venue check-in data will be retained on device for 21 days, per the DHSC. If an outbreak is identified at a location, its venue ID will be broadcast to all devices running the app -- and those that contain recent check-ins will generate an on-device match.

The DHSC says such a match may generate an alert and advice to the app user on what to do (e.g. whether to quarantine) -- "based on the level of risk."

The government says trials of the reformulated app on the Isle of Wight and with NHS Volunteer Responders have shown it to be "highly effective" when used in conjunction with traditional contact tracing to identify contacts of those who have tested positive for the novel coronavirus.

It had previously suggested there were issues related to limitations in Apple's and Google's APIs which made it difficult to effectively estimate the distance between devices which it said was needed to generate exposure notifications.

Talking up the impending launch of the app, health and social care secretary Matt Hancock suggested that the scannable venue codes will provide "an easy and simple way to collect contact details to support the NHS Test and Trace system." Although, businesses will need a fall-back system to collect data from patrons who do not have the app.

"We need to use every tool at our disposal to control the spread of the virus including cutting-edge technology. The launch of the app later this month across England and Wales is a defining moment and will aid our ability to contain the virus at a critical time," Hancock added.

U.K. businesses are being invited to download a QR code to display at their premise via gov.uk/create-coronavirus-qr-poster.

Reports last month in U.K. national press that suggested the app would abandon automatic contact tracing altogether appear to have been wide of the mark.