As far as we know X20 and X20 Pro will continue to be manufactured and sold.
It is just my gut feeling.

Personally I would never buy/sell a X20 Pro anymore with UHD2000 around the corner fixing its shortcomings.

Z1000 seems to sell far better than X20, in fact you just confirmed this yourself.

Value/money is better for X20 but Z1000 looks much nicer and not many appreciate a 42 cm wide box. Those which do want a full size box can still go for the UHD2000. Good marketing strategy Zidoo.

Hint for Futeko: You could add a second line of players sold via backorder? No idea how well it it will be received but many like to buy via you (I am one of them) and some models are not sold widely or at far higher prices. Many don't like buying in China directly either. The business risk in fact is minimal.

I do understand having a big stock with an undefined Brexit around the corner may cause bad sleeping.
