My ESP-01 module AT version:
AT+GMR
AT version:1.7.4.0(May 11 2020 19:13:04)
SDK version:3.0.4(9532ceb)
compile time:May 27 2020 10:12:17
Bin version(Wroom 02):1.7.4
OK
But WiFiEsp library show this warning on Serial monitor:
[WiFiEsp] Warning: Unsupported firmware 3.0.4
Your example (https://github.com/mathworks/thingspeak-arduino/blob/master/examples/ESP8266/via%20AT%20commands/WriteSingleField/WriteSingleField.ino) use WiFiEsp.h library.
My ESP-01 module AT version: AT+GMR AT version:1.7.4.0(May 11 2020 19:13:04) SDK version:3.0.4(9532ceb) compile time:May 27 2020 10:12:17 Bin version(Wroom 02):1.7.4 OK
But WiFiEsp library show this warning on Serial monitor:
[WiFiEsp] Warning: Unsupported firmware 3.0.4