Smartphone required for parking meters in Cambridge MA

So I find a legal street parking space in Harvard Square.  I park, get out, and face up to the parking meter.  The meter has a plaque on it directing me to download a "Pay Cambridge Parking Meters" app.  I guess the city fathers of Cambridge figure that all their citizens, or at least all Harvard students have smartphones.  I'm behind the times, I just have a dumbphone.  I finally wind up in a public parking garage that charges $16 an hour.