DFRobot_EC.cpp strupr error

Hi, i'm connecting the EC Sensor DFR0300, but when verifing the sketch on arduino ide (Arduino uno R4) i have an error about this command not supported “DFRobot_EC.cpp:85:5: error: 'strupr' was not declared in this scope”, i'm using the test program on the product wiki, the error seems in the libraries any idea how to solve the problem?