One more person has died in the Republic of Ireland with Covid-19, the National Public Health Emergency Team said.
Health officials in the Republic were notified of 24 more confirmed cases.
Dr Ronan Glynn, acting chief medical officer, said: "As of 5pm this evening, the Covid Tracker App had approximately 545,000 downloads.
"This is one more example of the solidarity and collective spirit that has characterised the Irish public's response to Covid-19 to date.
"The app is an important tool to support our contact tracing systems. It has the potential to reduce the time that people are active in the community with infection, which will have a significant impact on the transmission of the disease.
"The more people who download and use this app, the more effective it will be. It is a further opportunity for us to play our part in the response to Covid-19."
Meanwhile, no new deaths have been recorded with Covid-19 in Northern Ireland, the Department of Health said, leaving the total number of people who have died at 554.
Another five positive cases have been notified since Monday, bringing the total confirmed cases in the region to 5,761, according to the department.
Some 1,067 lab tests have been carried out on 806 people.
There are currently no Covid patients in Intensive Care Units across Northern Ireland, while 20 care homes are dealing with outbreaks of the virus.
