

Visa needed for connecting flight at Shenzhen airport
I am Dutch and on November 7, 2019, I will travel [for touristic purposes] from London (LHR) to Hanoi International airport in Vietnam with Shenzhen airlines. This will include a stop at Shenzhen Boa'an International airport (SZX) where I will have a connecting flight. In the 7 hours between my connecting flight from Shenzhen to Hanoi, I will not be leaving the airport.
My question now is if I need a visa or documents of any kind when travelling through Shenzhen's airport, as I cannot find concrete information on this and I was advised to contact Shenzhen Airlines. If so, will I need to get this in advance, or is this granted upon arrival?
I have attempted to contact Shenzhen Airlines, the Chinese Embassy in the Netherlands and other services but failed to receive a response, I hope you can help me as it's getting a bit stressful now!