LWM2M_CARRIER_LG_UPLUS_DEVICE_SERIAL_NO_IMEI

#define LWM2M_CARRIER_LG_UPLUS_DEVICE_SERIAL_NO_IMEI   0

#include <lib/bin/lwm2m_carrier/include/lwm2m_carrier.h>

Use the IMEI as the serial number for identification to the LG U+ network.