TOKYO -- When Japan rolled out its contact-tracing app last summer to fight the coronavirus, nobody expected that a major flaw affecting about one-third of users would go overlooked for more than four months.
The problem arose in September in the Android version of the app, which has been downloaded about 7.7 million times, the Ministry of Health, Labor and Welfare said Wednesday. People who came into contact with those who tested positive for COVID-19 received no notifications.
