After setting up their new phones and clicking on the app, users are greeted with a message reading: "Unfortunately you can't run this app". The message also offers a couple of possible reasons, such as the device being a company phone or that it is running another contact-tracing app.
Most likely, however, neither are the case. The app is having trouble when it is moved to a new phone, using Apple's usually seemless iCloud backup tool.
Thankfully, there is an easy fix. The technology can be turned on by heading to the settings.
While the error message only shows when a user opens up the app, the bug appears to mean that the contact-tracing technology does not work on the upgraded phone. As such, anyone who has not tried opening the app – which is intended to work in the background – may think they are tracking their exposures but are actually not having them logged at all.
The contact-tracing tools can be turned back on by opening up the Settings app, clicking notifications, choosing “exposure notifications” and then turning on the “allow notifications” option.
The problem can also be fixed by deleting and then re-installing the app. But that is not advised, since that also means getting rid of all the information that the phone has collected.
The problem appears to occur because of the tools that let people who get new iPhones transfer their data from their old ones. Backups in iCloud allow the new device to pull down all the data from the old – but do not appear to copy over the “allow notifications” setting, which initially arrives as a pop-up when the app is installed and needs to be done before the app will work.
That problem means that the issue could theoretically affect users of other new devices that are not the iPhone 12. People who are transferring onto different Apple phones might also find their contact-tracing options have been switched off.
The NHS does maintain a list of “compatible devices”, which does not include the iPhone 12 or 12 Pro, or other new phones such as Google’s Pixel 5. But that list appears to be very incomplete, and the app works fine on a number of devices that are not listed.