The phone numbers library isn't just counting digits; it has a database of which area codes exist (as well as other lesser-known rules, depending on the country

The phone numbers library isn't just counting digits; it has a database of which area codes exist (as well as other lesser-known rules, depending on the country). This makes it more effective at filtering out invalid/fake phone numbers, but it does mean you need to stay on top of the latest version as its database changes over time.