Sim900a AT+HTTPREAD does not get fully answer changed the firmware on SIM900B

try to send get request http://dummy.restapiexample.com/api/v1/employee/1
AT+HTTPACTION=0returned +HTTPACTION:0,200,98

but, when I try to read (AT+HTTPREAD or AT+HTTPREAD=0,98)the response data
I got broken response

expected result:

+HTTPREAD:98
{"id":"1","employee_name":"Shibani","employee_salary":"999","employee_age":"0","profile_image":""}


and actual results: 

+HTTPREAD:98
{"id":"1","employee_name":"Shibani","employee_salary":"999","empe_"0"olme"

+HTTPREAD:98
{"id":"1","employee_name":"Shibani","employee_salary":"999","empe_"0"fea"}

+HTTPREAD:98
{"id":"1","employee_name":"Shibani","employee_salary":"999""pea:,piig"

+HTTPREAD:98
{"id":"1","employee_name":"Shibani","employee_salary":"999",moeg""reae}


my Arduino code looks like that

void setup() {
  Serial.begin(9600);
  mySerial.begin(57600);
  delay(5000);
  mySerial.println("AT");
  Serial.println("End of the setup");
}

void loop() {
  if (mySerial.available())
    Serial.write(mySerial.read());
  if (Serial.available())
    mySerial.write(Serial.read());
}
Apparently you were running software serial at too high of a baud rate (57600) and bringing it down to 9600 fixed the issue.