The UK is reportedly now building a second contact-tracing app to work with Apple and Google's framework

• The UK is currently tuning trials for its contact-tracing app which it built without Apple and Google's specialized contact-tracing API.
• Meanwhile, it's quietly building a second app which does use the Apple-Google API, sources told The Financial Times.
• Although originally the UK said it would reject the Apple-Google API, it ran into significant technical difficulties with its first app, the sources said.
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The UK appears to be hedging its bets by building two contact-tracing apps, the Financial Times reports.

Two sources familiar with the project told the FT that NHSX, the NHS' digital experimental division, is now building a second contact tracing app alongside the contact-tracing app already being tested on the Isle of Wight.

Unlike the app currently being tested, the new app will be built using Apple and Google's specialized contact-tracing API.

One source said this was because the government ran into significant technical difficulties getting its app to work without the new API. Specifically, the source said it had run into problems with iPhone compatibility and battery drain. "These technical details end up being quite important," the source said.

NHSX, Apple, and Google did not immediately respond to Business Insider's request for comment.

Centralized versus decentralized

The UK said in late April it would be rejecting Apple and Google's new API because the tech companies stipulate that all apps built using their framework must be "decentralized." This means all the data processing takes place on a user's handset, and can't be stored externally on a database.

Google and Apple say this is because decentralized apps are more private and a central database is more vulnerable to large-scale hacking. Cybersecurity experts also believe decentralized apps mitigate the possibility of that data later being used for government surveillance.

Many countries in Europe opted for Apple and Google's API, but Britain and France said they would build their own centralized apps because it would allow government to analyze the data more easily.

In the UK's case, its app ran into problems with functionality whenever the app would run in the background. On iPhones and some newer Android phones, apps are not able to transmit Bluetooth signals while running in the background. As the app works by having phones send out Bluetooth signals to recognize when they are close to another user, this meant in some instances two iPhone users wouldn't have their proximity logged even when standing close together.

Documents spotted this week showed the government recently employed an IT firm to investigate the possibility of integrating with the Apple-Google API, after having initially said it would do without it.

It's not clear at this stage which of the two apps the NHS will select, or whether it could end up launching both. France also appears to have run into technical difficulties developing its app without the API, as its digital minister attacked Apple saying the company could have helped France's app run more smoothly on iPhones.