Police officials in England and Wales have been told they can download the NHS Covid-19 app on their personal smartphones and use it at work.
The National Council of Police Council (NPCC) issued the guidelines after conducting its own technical review of the software.
Individual officers and other police staff will be notified on Wednesday.
The NPCC had earlier advised officials not to download the app on any device, while it reviewed its impact.
And they will still be told not to install it on work handsets.
These usually have their Bluetooth functionality disabled.
And the automatic contact-detection process is based on Bluetooth’s wireless signals.
An NPCC spokesman told BBC News that some employees involved in the covert and special operations, as well as other sensitive roles, would be told not to consider installing the app on any phone until further guidance.
“It is important that we are confident that the NHS application will continue to work for officers and employees across the country,” he said.
“And for this reason we have recommended that officers and employees download the application to their personal devices as opposed to their work devices.”
After making several changes to the previous test version, the NHS Covid-19 was widely publicized on Thursday.
It follows the release of similar software in Scotland and Northern Ireland.
The NPCC was asked to change its policy by the Police Federation of England and Wales (PFW), which represents about 120,000 officers.
He said the NPCC had shown a willingness to be cautious, but the welfare of its members was “absolutely paramount”.
John Apter, who is also the president of the federation, said.
“It’s definitely a personal decision if officers want to download the app now.
“However, we will encourage and request [them] To do so. “
NHS Covid-19 logs when two people’s phones come close to each other.
If one is later confirmed to have coronavirus, the other may be asked to self-isolate automatically for a fortnight.
This app is designed to keep the identities of both parties secret.
Other functions include a means for users to log a visit to restaurants and other leisure sites, via a QR-barcode scan, and then receive a notification if the location is later linked to an outbreak.
Health Secretary Matt Hancock said the app had been downloaded more than 12.4 million times by 12:00 on Monday.