Problems linking using MBedStudio or Kiel Cloud Studio

[GTNicholson]

I don't seem to be able to get this library to link. I get four similar error messages
for example:
Error: L6218E: Undefined symbol eMBRegCoilsCB(unsigned char*, unsigned short, unsigned short, eMBRegisterMode) (referred from BUILD/LPC1768/ARMC6/mbed-modbus/mbfunccoils.o).
Would very much appreciate any help in resolving this.