I am using an inductive proximity sensor having an operating voltage of 5V with raspberry pi 3B+. Sensor has been given 5V from Pi. On sensing metal, output of this sensor is approximately 4.5-5Volts. I have connected this output to one of GPIO pins of raspberry pi. Raspberry Pi is working fine. But as per specifications, Pi can not tolerate voltage above 3.3V. I am not getting how could GPIO pin tolerate voltage above 3.3V. Is this possible?