Finally!
I was able to update to 6.4.14.
Used MiFlash with China dev ROM.
Installed twrp
Flashed, via twrp, 6.4.14.
Last week I was unable to used MiFlash due to PC issue. This time I changed PC and everything works smooth.
Thanks to all for the help
You can install new versions of this rom via Updater app, no need to follow such a long way.