Just to clarify:
Mi Band 4 non-NFC: Both Global and China versions have the same firmware.
Mi Band 4 NFC: The firmware was the same as for non-NFC band until Mi Fit 4.0.5, when firmwares versions split up to 1.0.5.10 and 1.0.5.22 for non-NFC and NFC devices respectively. Since then they have...