A new coronavirus contact-tracing app has been launched in Jersey.
Anonymous codes exchanged via Bluetooth will alert a person if they have been in close contact with someone who has tested positive.
People with confirmed Covid-19 tests will be asked to upload their results to the alert app by the contact-tracing team.
The government said its introduction would provide an "additional level of prevention and protection".
Downloading the app is not mandatory, but employers will be targeted to promote its use among workers, the government said.
This would include public sector employees such as police officers and healthcare staff.
Digital Jersey chief executive Tony Morretta said the app was a "complementary approach" to other coronavirus measures in place.
He added no personal data would be collected by it, including the name, age, or address of an individual.
The app has been designed using Apple and Google technology, and does not use GPS.
Several times a day, the app will check the "random IDs" a phone has received and cross-check this against those assigned to people who have been diagnosed with the virus in the last 14 days.
Anyone who gets an alert will be asked to speak with the contact-tracing team for advice on isolation requirements.
Dr Ivan Muscat, the island's deputy medical officer of health, said: "The more people who download the app, the more benefit we can gain from it.
"Given the collective and robust response we have seen from islanders over the last six months, I am sure that there will be a significant uptake."
Inbound travellers will also be "heavily encouraged" to download, with plans to develop its compatibility with the NHS Covid-19 app.
Jersey's app is only available to download on the iPhone 6S, or the Android 6 Marshmallow, and newer models.