...here "Latest news from "Commissioner's Office" issued 17.04.:
For F visa: What is an "additional visa notification letter" ?
Answer see in this post comments from a reader in Hangzhou. But how to apply this for example for Dongguan when your visa is expired and you are in Hong Kong and you cannot go to Dongguan to get this "visa notification letter" ?
Today front page SCMP: "New curbs on travel to the mainland" + on Page 3 "Europeans seek talks over visa restrictions"