platform-ststm32: In the v14.0.0 version, the serial port cannot work

First of all thanks to all contributors for making it easy to use stm32. I tried to use version 14 today, the serial port does not work, but there is no problem with version 13. The hardware I use is https://github.com/WeActTC/BluePill-Plus. Hope you can get help, thank you very much.

This is my code

#include <Arduino.h>

void setup() {
   pinMode(PB_2, OUTPUT);

   Serial.begin(115200);
}

void loop() {
   digitalWrite(PB_2, HIGH);
   Serial.print("0.0");
   delay(1000);
   digitalWrite(PB_2, LOW);
   Serial.print("1.1");
   delay(1000);
}