Update README.md

Author: khoih-prog

README.md

@@ -152,7 +152,7 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
 ## Prerequisites
 
 1. [`Arduino IDE 1.8.15+` for Arduino](https://www.arduino.cc/en/Main/Software)
-2. [`Earle Philhower's arduino-pico core v1.8.1+`](https://github.com/earlephilhower/arduino-pico) for RP2040-based boards such as **RASPBERRY_PI_PICO, ADAFRUIT_FEATHER_RP2040 and GENERIC_RP2040**, etc. [![GitHub release](https://img.shields.io/github/release/earlephilhower/arduino-pico.svg)](https://github.com/earlephilhower/arduino-pico/releases/latest)
+2. [`Earle Philhower's arduino-pico core v1.9.4+`](https://github.com/earlephilhower/arduino-pico) for RP2040-based boards such as **RASPBERRY_PI_PICO, ADAFRUIT_FEATHER_RP2040 and GENERIC_RP2040**, etc. [![GitHub release](https://img.shields.io/github/release/earlephilhower/arduino-pico.svg)](https://github.com/earlephilhower/arduino-pico/releases/latest)
 
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