'Possible Covid-19 exposure': NHS app update fixes bug that led to worrying coronavirus alerts

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The NHS Covid-19 app has been updated to remove a bug that left users feeling confused and worried.

Among a number of features, the official app watches for connections with other phones, as a way of logging people their owner might have met. If a person within that network later registers themselves as testing positive, an alert will be sent out to affected phones with advice, which might include an instruction to self-isolate.

But since the app launched last month, users found themselves receiving “phantom" versions of those notifications. Messages would pop up that suggested the users might have been exposed to someone positive, but gave no further information.

“Possible Covid-19 exposure,” the notification read. "Someone you were near reported having Covid-19. Exposure date, duration and signal strength have been saved."

Clicking into the message would give no information about whether the user had really been exposed, or whether they should take any action in response.

That was because the messages were actually just a first stage of the alert system. The “possible exposure” notification meant only that a person might have been in enough contact with someone to trigger the app –  not that they definitely had.

Whether they really had is decided after, when the app scans the details on the exposure and decides whether that person is at risk. If they are, they might be instructed to self-isolate with another notification, though many users of the app have not received such messages despite getting. the first notification.

A new update to the app add a “better notification for potential exposures”, according to the update notes on the App Store.

Now, users will be able to click through to find out more information about the exposure and what, if anything, they should do.

The update does not remove the messages. They are a part of the Apple and Google technology that underpins the app.

Instead, they will now be followed by an explanation that makes clear to users who receive them what they should do.

“Covid-19 Exposure Check Complete,” that follow-up notification will read. "Don't worry, we have assessed your risk and there is no need to take action at this time.

"Please continue to stay alert and follow the latest advice on social distancing."