HopeRF library - Error message

Hi,
I want make a wirelles Temp sensor usin Arduino,Dallas temp sensor and HM-T868S as Transmitter (HM-R868S as receiver). But when I write program (I'm using HopeRF library by Mikem) it says error message:

C:\Program Files (x86)\Arduino\libraries\HopeRF\HRFMessage.cpp: In function 'uint16_t hrf_crc(uint8_t*, uint8_t)':
C:\Program Files (x86)\Arduino\libraries\HopeRF\HRFMessage.cpp:22: error: '_crc_ccitt_update' was not declared in this scope
C:\Program Files (x86)\Arduino\libraries\HopeRF\HRFMessage.cpp: In member function 'virtual uint8_t HRFMessage::send(uint8_t*, uint8_t)':
C:\Program Files (x86)\Arduino\libraries\HopeRF\HRFMessage.cpp:49: error: '_crc_ccitt_update' was not declared in this scope

My code:

#include <OneWire.h>
#include <DallasTemperature.h>
#include <HRFMessage.h>

// Declare the HRFMessage to use Serial for IO with the HM-TR module
HRFMessage client(&Serial);
long      lastSendTime = 0;

//Define Sensor
#define ONE_WIRE_PIN 8

OneWire oneWire(ONE_WIRE_PIN);
DallasTemperature sensors(&oneWire);

void setup()
{
    Serial.begin(9600);  //Begin communication
    
    sensors.begin();  //Begin sensor

}

void loop()
{
  //Get temp from Dallas sensor
  sensors.requestTemperatures();
  char C = sensors.getTempCByIndex(0);
  
  
  // Send a message to the server at most once a second
  long thisTime = millis();
  if (thisTime > lastSendTime + 1000)
  {
    client.send((uint8_t*)C, 6); // Includes the NUL at the end of the string
    lastSendTime = thisTime;
  }

  
}