Warning: ignoring packed attribute because of unpacked non-POD field
⚠️ CAUTION: SLIPPERY FLOOR ⚠️
The Arduino Library Manager installs the ArduinoJson version 6 by default.However, using version 5 is highly recommended because version 6 is still in beta stage.
Open the Arduino Library Manager and make sure that ArduinoJson version 5.13.4 is installed.
If you pass the flag --fpack-struct to the compiler, it will generate the following warning:
warning: ignoring packed attribute because of unpacked non-POD field
No solution has been found so far: you need to remove that flag if you want to get rid of that warning.