For iPhones, Batphone works with iOS 10+. Apple introduced "Emergency Bypass" which allows calls from certain contacts to bypass silent mode. It's a useful feature but you probably don't want all the calls from a contact to ring your phone.
We created Batphone so you can have a new dedicated phone number that bypasses silent mode for emergencies.
Some Android versions have the ability to bypass silent mode but we don't officially support them. It's best to check what features your phone has before signing up for Batphone.