ESP8266 connection to Google giving getFreeContStack issues

Hello,

I'm trying to connect my ESP8266 to a google sheet using the working example given in the Electronicsguy tutorial but I am getting the below errors about there being no member named 'getFreeContStack'.

Does anyone know where I'm going wrong?

Arduino: 1.8.12 (Windows 10), Board: "Generic ESP8266 Module, Serial, 80 MHz, 40MHz, DIO, 115200, 512K (no SPIFFS), nodemcu, Disabled, None"

C:\Users.........s\ESP8266-master\HTTPSRedirect\GoogleDocs\GoogleDocs.ino: In function 'void setup()':

GoogleDocs:54:27: error: 'class EspClass' has no member named 'getFreeContStack'

free_stack_before = ESP.getFreeContStack();

^

GoogleDocs:77:11: error: 'class HTTPSRedirect' has no member named 'setInsecure'

client->setInsecure();

^

GoogleDocs:114:65: error: 'class EspClass' has no member named 'getFreeContStack'

payload = payload_base + """ + ESP.getFreeHeap() + "," + ESP.getFreeContStack() + ""}";

^

GoogleDocs:128:65: error: 'class EspClass' has no member named 'getFreeContStack'

payload = payload_base + """ + ESP.getFreeHeap() + "," + ESP.getFreeContStack() + ""}";

^

GoogleDocs:138:65: error: 'class EspClass' has no member named 'getFreeContStack'

payload = payload_base + """ + ESP.getFreeHeap() + "," + ESP.getFreeContStack() + ""}";

^

GoogleDocs:145:41: error: 'class EspClass' has no member named 'getFreeContStack'

Serial.printf("Free stack: %u\n", ESP.getFreeContStack());

^

C:\Users.........ESP8266-master\HTTPSRedirect\GoogleDocs\GoogleDocs.ino: In function 'void loop()':

GoogleDocs:162:29: error: 'class EspClass' has no member named 'getFreeContStack'

free_stack_before = ESP.getFreeContStack();

^

GoogleDocs:164:13: error: 'class HTTPSRedirect' has no member named 'setInsecure'

client->setInsecure();

^

GoogleDocs:201:65: error: 'class EspClass' has no member named 'getFreeContStack'

payload = payload_base + """ + ESP.getFreeHeap() + "," + ESP.getFreeContStack() + ""}";

^

GoogleDocs:226:44: error: 'class EspClass' has no member named 'getFreeContStack'

Serial.printf("Final stack: %u\n", ESP.getFreeContStack());

^

exit status 1
'class EspClass' has no member named 'getFreeContStack'