Like other apps that take advantage of the Exposure Notification API from Apple and Google, NHS COVID-19 is created to track who people come into contact with each other using Bluetooth, providing a notification if one of those people later comes down with the coronavirus.
"We have worked closely with the app development team to ensure it works seamlessly across Wales and England, providing people with the right advice based on where they live". The government said businesses will be required by law to display the official National Health Service (NHS) quick response (QR) code posters so that people can check-in at different premises with the new app. Features of the app include contact-tracing using Bluetooth, risk alerts based on postcode district, QR check-in at venues, symptom checker and test bookings.
Data shows 411 people who tested positive for Covid-19 in Redbridge were transferred to the Test and Trace service between May 28 and September 9.
Switching the NHS COVID-19 app to a decentralized architecture has allowed it to plug into coronavirus exposure notification APIs developed by Apple and Google - resolving technical problems related to device detection which caused problems for the earlier version of the app.
A further 924 close contacts were identified in this way in Redbridge - also referred to as "non-complex" cases, meaning they could be dealt with through a call centre or online.
Early users who tried to download it through the Google Play Store found that they were told the app was still the early version, which was used in tests on the Isle of Wight and in Newham in London.
Both Scotland and Northern Ireland have already introduced their own individual contact tracing apps, which users can switch to should they visit either country, following the delay of the original NHS software.
"We have worked extensively with tech companies, global partners, and privacy and medical experts - and learned from the trials - to develop an app that is secure, simple to use and will help keep our country safe", UK Health Secretary Matt Hancock said.
The more people who download and use the app, the easier it will be to trace people who have come in to contact with the virus.
The England and Wales app does have some of unique quirks - as the government has opted to pack in multiple features, rather than limiting it to only exposure notifications.
It will alert you if you have been in "close contact" with someone who has been diagnosed with coronavirus, and will also alert others if you yourself receive a positive test result.
A built in QR scanner lets you check in to participating venues, saving you from filling out a form or downloading another app. "So if we don't speed up testing then the app is functionally useless".
"I strongly encourage everyone in Wales to download and use the app to keep Wales safe". It requires a device running iOS 13.5 or Android 6.0 or later.