The French digital minister said his coronavirus contact tracking app has been downloaded 600,000 times since it became available on Tuesday afternoon.
StopCovid France is designed to prevent a second wave of infections by using smartphone registries to warn users if they have been close to someone who later tested positive for the virus.
But a last minute launch delay has led some citizens to download the wrong product.
England has yet to confirm when its app will be implemented nationally.
Matt Hancock, health secretary, had initially stated that it would be by June 1st, and later suggested that it would be in the middle of next week.
But the BBC has learned that it is unlikely to be before June 15th and could go up to July.
This is partly due to delays in the release of a second version of the software on the Isle of Wight, where it is being tested.
The update will add symptoms including loss of taste and smell to a self-diagnosis questionnaire next week or shortly thereafter.
It will also begin to provide users at risk with a code to access a separate website when they book a medical test. This will allow you to return the result to them, indicating whether they were positive or negative, through the app.
Both the UK and France have created their own apps based on a “centralized” design.
In contrast, Latvia, Italy and Switzerland have released apps based on “decentralized” technology developed by Apple and Google.
Proponents of the centralized approach say it provides epidemiologists with more data to analyze, helping them better identify contagion alerts. In addition, they are not limited by the rules imposed by the two technology companies, such as a ban on collecting location data.
Proponents of the decentralized model say it better protects user anonymity and privacy.
The introduction of StopCovid France has sparked controversy.
Hundreds of academics signed a letter in April raising concerns that the collected data could be reused for mass surveillance purposes.
Then there was a dispute over the government’s refusal to give parliamentarians a vote on the issue, which was resolved only after the ministers gave non-binding votes to the Senate and National Assembly.
Both eventually gave the app the green light. And the country’s data privacy watchdog also approved the implementation after making its own review, although it required some changes to the app’s wording.
But questions remain about how many people will voluntarily install it: the more they do it, the better it should work.
Digital Minister Cedric O said he was satisfied with the initial acceptance.
“As of this morning, 600,000 people have been able to download the app, so it’s a great start,” he told France 2 TV channel.
“We are very happy with its beginning, but obviously several million French people must have it”.
He refused to give an exact target. But he previously said that an advertising campaign would initially focus on city dwellers – especially those who use public transportation, restaurants and supermarkets at peak times – as they were among those most likely to spread Covid-19.
The French government had stated that the app would be released on Tuesday at noon.
But StopCovid France didn’t appear on Google Play until late Tuesday afternoon, and then a few hours later on the Apple App Store.
One consequence of this was that a Catalan health information app with a similar name – Stop Covid19 CAT – was mistakenly downloaded by many in the meantime, causing France’s download rankings in a short time.
The only explanation given for the delay was the need to make last minute “technical adjustments”.
Contact tracking apps are supposed to complement the work done by humans by questioning those diagnosed with the disease. It is not clear whether the limits of relying on Bluetooth can be overcome to avoid capturing too many false flags.
Further details on the UK efforts can be provided when Baroness Dido Harding, who heads the government’s Test and Trace program, and Prof Christophe Fraser, who advises the national health system on the project, provide evidence to Parliament this afternoon.
It is not yet clear whether other parts of the UK will adopt the app or opt for an alternative approach.
Earlier, Northern Ireland’s chief scientific advisor had told the Stormont health committee that he planned to focus on manual contact tracking, saying he thought the app’s usefulness had been overstated.
“At best, it’s an addition,” said prof. Ian Young.
Health Minister Robin Swann added that she feared that the app would be unattractive to users because of concerns about battery drain and that people at the end of a phone were already proving effective.