@berkseo
thanks for your info.
I setup a new installation of the Arduino IDE as mentioned.
But when I want to compile the pws_e73c_nrf52840_test, I get two kinds of compile error:

- In file included from C:\Users\User\Documents\Arduino\libraries\MySensors/hal/transport/NRF5_ESB/driver/Radio.cpp:1:0,
                 from C:\Users\User\Documents\Arduino\libraries\MySensors/MySensors.h:364,
                 from C:\Users\User\Documents\Arduino\pws_e73c_nrf52840_test\pws_e73c_nrf52840_test.ino:98:
C:\Users\User\Documents\Arduino\libraries\MySensors/hal/transport/NRF5_ESB/driver/Radio.h:68:17: error: 'RADIO_MODE_MODE_Nrf_250Kbit' was not declared in this scope
  NRF5_250KBPS = RADIO_MODE_MODE_Nrf_250Kbit, // Deprecated!!!

- C:\Users\User\Documents\Arduino\pws_e73c_nrf52840_test\pws_e73c_nrf52840_test.ino: In function 'void presentation()':
pws_e73c_nrf52840_test:141:18: error: 'RED_LED' was not declared in this scope
     blinky(1, 1, RED_LED);
These are for: RED_LED, GREEN_LED, PIN_POWER_PWS, PIN_SENS_PWS

In this case there is also a MyBoardNRF5 in the github zip. Do I need to adapt something else in this case for the E73C_PWS_MODULE?
Did you also add the nrf52840 for the MySensors board definitions?

Thanks for your help.