Mobile phones can give a lot away about us – whether we want them to or not. A Japanese firm has faced criticism after its ‘boyfriend tracker’ app Kare Log allowed people suspicious of their partners to track their movements and the calls they made – completely undetected.

As The Telegraph reports, the app was explicitly targeted at women who wanted to know where there husband was. A basic monthly charge provided the end-user with the location of the phone and the amount of energy left in the its battery. For an extra charge, the app would provide access to the phone’s call log, including dates, times and durations, as well as details of other apps that had been installed.

The app ran entirely in the background without so much as an on-screen icon, making it fall very much (and quite literally) into the realm of spyware.

With a claimed 24,000 downloads in ten weeks there are potentially plenty of Japanese citizens under surveillance from their partners. Japan’s Ministry of Internal Affairs and Communications wasn’t impressed by the app. The Mainichi Daily News quotes a statement from the ministry noting: “The consent of a tracked individual is very important. There were problems with the way Kare Log was advertised.”

Now in the face of complaints about its privacy invading nature, The Telegraph says that developer Manuscript has relaunched the app as a ‘location service for lovers’ that is designed for couples to share information about each other.

There will probably be a few disappointed, insecure Japanese women out there as a result of the change – and quite a few relieved boyfriends and husbands.