CAUTION: SLIPPERY FLOORThe 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 is installed.
There is currently a bug in the Arduino Core for Adafruit WICED Feather causing the following error:
error: cannot convert 'err_t' to 'err_t (*)()
See issue #404