v1.4.0 to add support to RP2040-based boards

11. [`Arduino mbed_rp2040 core 2.1.0+`](https://github.com/arduino/ArduinoCore-mbed) for Arduino (Use Arduino Board Manager) RP2040-based boards, such as RASPBERRY_PI_PICO. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-mbed.svg)](https://github.com/arduino/ArduinoCore-mbed/releases/latest)
12. [`Earle Philhower's arduino-pico core v1.4.0+`](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)

README.md

@@ -270,17 +270,19 @@ This [**GSM_Generic** library](https://github.com/khoih-prog/GSM_Generic) curren
 
 ## Prerequisites
 
- 1. [`Arduino IDE 1.8.13+` for Arduino](https://www.arduino.cc/en/Main/Software)
+ 1. [`Arduino IDE 1.8.15+` for Arduino](https://www.arduino.cc/en/Main/Software)
  2. [`Teensy core v1.51`](https://www.pjrc.com/teensy/td_download.html) for Teensy (4.0, 3.6, 3.5, 3,2, 3.1, 3.0) boards and [`Teensy core v1.53+`](https://www.pjrc.com/teensy/td_download.html) for Teensy 4.1 boards using NativeEthernet.
  3. [`Arduino SAM DUE core v1.6.12+`](https://www.arduino.cc/en/Guide/ArduinoDue) for SAM DUE ARM Cortex-M3 boards.
  4. [`Arduino SAMD core 1.8.11+`](https://www.arduino.cc/en/Guide/ArduinoM0) for SAMD ARM Cortex-M0+ boards. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-samd.svg)](https://github.com/arduino/ArduinoCore-samd/releases/latest)
- 5. [`Adafruit SAMD core 1.6.7+`](https://www.adafruit.com/) for SAMD ARM Cortex-M0+ and M4 boards (Nano 33 IoT, etc.). [![GitHub release](https://img.shields.io/github/release/adafruit/ArduinoCore-samd.svg)](https://github.com/adafruit/ArduinoCore-samd/releases/latest)
+ 5. [`Adafruit SAMD core 1.7.2+`](https://www.adafruit.com/) for SAMD ARM Cortex-M0+ and M4 boards (Nano 33 IoT, etc.). [![GitHub release](https://img.shields.io/github/release/adafruit/ArduinoCore-samd.svg)](https://github.com/adafruit/ArduinoCore-samd/releases/latest)
  6. [`Seeeduino SAMD core 1.8.1+`](https://github.com/Seeed-Studio/ArduinoCore-samd) for SAMD21/SAMD51 boards (XIAO M0, Wio Terminal, etc.). [![Latest release](https://img.shields.io/github/release/Seeed-Studio/ArduinoCore-samd.svg)](https://github.com/Seeed-Studio/ArduinoCore-samd/releases/latest/)
- 7. [`Adafruit nRF52 v0.21.0+`](https://www.adafruit.com) for nRF52 boards such as Adafruit NRF52840_FEATHER, NRF52832_FEATHER, NRF52840_FEATHER_SENSE, NRF52840_ITSYBITSY, NRF52840_CIRCUITPLAY, NRF52840_CLUE, NRF52840_METRO, NRF52840_PCA10056, PARTICLE_XENON, **NINA_B302_ublox**, etc. [![GitHub release](https://img.shields.io/github/release/adafruit/Adafruit_nRF52_Arduino.svg)](https://github.com/adafruit/Adafruit_nRF52_Arduino/releases/latest)
- 8. [`ESP8266 Core 2.7.4+`](https://github.com/esp8266/Arduino) for ESP8266-based boards. [![Latest release](https://img.shields.io/github/release/esp8266/Arduino.svg)](https://github.com/esp8266/Arduino/releases/latest/). To use ESP8266 core 2.7.1+ for LittleFS. 
+ 7. [`Adafruit nRF52 v0.23.0+`](https://www.adafruit.com) for nRF52 boards such as Adafruit NRF52840_FEATHER, NRF52832_FEATHER, NRF52840_FEATHER_SENSE, NRF52840_ITSYBITSY, NRF52840_CIRCUITPLAY, NRF52840_CLUE, NRF52840_METRO, NRF52840_PCA10056, PARTICLE_XENON, **NINA_B302_ublox**, etc. [![GitHub release](https://img.shields.io/github/release/adafruit/Adafruit_nRF52_Arduino.svg)](https://github.com/adafruit/Adafruit_nRF52_Arduino/releases/latest)
+ 8. [`ESP8266 Core 3.0.1+`](https://github.com/esp8266/Arduino) for ESP8266-based boards. [![Latest release](https://img.shields.io/github/release/esp8266/Arduino.svg)](https://github.com/esp8266/Arduino/releases/latest/). To use ESP8266 core 2.7.1+ for LittleFS. 
  9. [`ESP32 Core 1.0.6+`](https://github.com/espressif/arduino-esp32) for ESP32-based boards. [![Latest release](https://img.shields.io/github/release/espressif/arduino-esp32.svg)](https://github.com/espressif/arduino-esp32/releases/latest/)
 10. [`ESP32-S2/C3 Core 1.0.6+`](https://github.com/espressif/arduino-esp32) for ESP32-S2/C3-based boards. Must follow [HOWTO Install esp32 core for ESP32-S2 (Saola, AI-Thinker ESP-12K) and ESP32-C3 boards into Arduino IDE](#howto-install-esp32-core-for-esp32-s2-saola-ai-thinker-esp-12k-and-esp32-c3-boards-into-arduino-ide).
 11. [`Arduino Core for STM32 v2.0.0+`](https://github.com/stm32duino/Arduino_Core_STM32) for STM32 boards. [![GitHub release](https://img.shields.io/github/release/stm32duino/Arduino_Core_STM32.svg)](https://github.com/stm32duino/Arduino_Core_STM32/releases/latest)
+12. [`Arduino mbed_rp2040 core 2.2.0+`](https://github.com/arduino/ArduinoCore-mbed) for Arduino (Use Arduino Board Manager) RP2040-based boards, such as RASPBERRY_PI_PICO. [![GitHub release](https://img.shields.io/github/release/arduino/ArduinoCore-mbed.svg)](https://github.com/arduino/ArduinoCore-mbed/releases/latest)
+13. [`Earle Philhower's arduino-pico core v1.8.8+`](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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