It has just been abandoned. It works using bluetooth to identify other phones with bluetooth switched on nearby, and stores the identity of those phones. Then if the user tests positive for the virus, the phones stored will receive alerts telling them they have been exposed, and to self isolate for 14 days.
Problem is it doesn't work at all well with iPhones, and with android phones it is not that reliable either. In areas with a lot of metal, such as on a bus, it won't pick up the signals.
Government now seeking to use Apple and Google technology to try and make it work, rather then trying to create their own. I wouldn't hold your breath.