[Hong Kong] The LeaveHomeSafe COVID-19 exposure notification mobile app was launched on 16 Nov. The app aims to encourage the public to keep a more precise record of their whereabouts and help break the chain of COVID-19 transmissions. The LeaveHomeSafe venue QR codes are available at 67,000 public and private venues, 18,000 taxis and the app has been downloaded over 430,000 times. When entering a venue, open the App, click “Enter” to allow access to the camera function of your phone and scan the specific QR code displayed at the venue. Press “Leave” when you leave the venue to complete the record of your visit. The “LeaveHomeSafe” mobile app upholds the principle of protecting personal data privacy and as such, user registration is not required. No positioning services or any other data of the user’s mobile phones will be accessed. Venue check-in data is also encrypted and saved on the user’s device only and will not be uploaded to the Government or any other systems. Check-in data will be kept on the user’s mobile phones for 31 days and will be erased automatically.