Among other ways, you can find the Z-Stack Code Revision (“ZStack CodeRevision”) in the backup file, so just download the JSON backup file and you should find that listed somewhere at the end of it. More tips here → ITead's "Sonoff Zigbee 3.0 USB Dongle Plus" (model "ZBDongle-P") based on Texas Instruments CC2652P +20dBm radio SoC/MCU