The proprietary %XANTDETMAGPIO command reads the MAGPIO pin status to detect if the antenna is connected. The antenna is detected when the pin is grounded to DC. v1.1.x v1.2.x v1.3.x pti_v1.1.x≥1
This command can be used, for example, in device production testing provided that the necessary circuitry between an MAGPIO pin and the antenna is in place. See Antenna presence test using MAGPIO in nWP033 - nRF9160 Antenna and RF Interface Guidelines.