I had heard they might sell two...but have seen no indication of it. In fact, as Jobjed showed us, all four are still docked in Greece.The first domestic zubr was launched last year AFAIK.
Since china now owns 7 of them, plus another under construction, i really doubt that they will build further. The issue is if they will develop a new large hovercraft in the future, since this is 1980´s technology.
Greece sold its zubr fleet to china.
I do not think China is buying Greek Zubrs since they now can build their own so readily.
Right now there are four in China we know of...and we have just seen a picture that shows a fifth supposedly.
If they have five, I expect they will build at least one more...and they may build even more. I believe the Zubr is a good vessel for the PLAN in the SCS.
If China only wanted four to six, they would not (IMHO) gone to the trouble of developing their own manufacturing capability. They would have bought the Ukraine Zubrs and the Greeks.
But they did develop the capability and have built two and maybe three now. If they have built that many, then I expect they are going to build more.