What does baseband version unknown mean?

The baseband version represents the version of the firmware installed on the device which is needed to establish communication between the mobile network and the integrated cellular radio hardware .22 Haz 2015

How to check the current software version on your mobile device

Baseband is firmware that controls all radio devices on the phone, including GPS, wi-fi, Bluetooth, NFC, cell data and voice, etc . because these functions are highly regulated and certified, they are separate from the main operating system. AP software version is characterized by the Android version and kernel version.