Cricket (and its parent network AT&T) now requires VoLTE (Voice over LTE) for all calls. The iPhone 5s does not support this technology, meaning you cannot make or receive standard phone calls even if you have a signal.
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The iPhone 5s is stuck on iOS 12 , which no longer receives security updates or feature improvements. Cricket (and its parent network AT&T) now requires
Cricket's official Bring Your Own Device (BYOD) list currently only supports iPhone 6 and later . Attempting to activate an older device like the 5s may result in your account being locked or receiving no service. Performance & Security Limitations Cricket's official Bring Your Own Device (BYOD) list