I bought 2 units of da fang before reading this forum. A bit regret.
The connection is poor. Pairing took me 15 times of retry.

Which is the best firmware?
I tested many firmware, basically the 5.5.1.194 is the most stable one. (BTW, i am using digi as internet.)
I even tested the custom hack firmware. End up given up because digi cannot port forward, it is useless to have RSTP.

The another unit is still sealed and leaving there. No mood to touch it anymore.
This Dafang function is much better than my mijia 360, but the realibility is shit.

I tried many version.
Only .194 work best for me.

I don't know either i got a lemon unit or digi problem.

Some period of time, the connection work normal.