No, your emergency contacts do not need to download the app to receive emergency alerts.
You simply need to add their cell phone numbers as emergency contacts within the app. When you trigger your device, your emergency contacts will receive phone calls and text messages from an American phone number.
We recommend that you ask your emergency contacts to add the Plegium phone numbers to their contact list for easy identification. Phone calls will come from (312) 626-5076, and text messages from (478) 288-8999.