In the past you could have a Chinese visa in an old passport, and use it with a new passport - is this still possible?
Second question - last time I renewed my UK passport it was at the consulate in Hong Kong, and the clerk asked me if there were any valid visas I wanted to keep before clipping the corners off the old passport. As the passport applications now need to be sent to the UK, what happens to the old passport? Do you need to send it with your application for a new passport? If yes, what would happen to existing visas in the old passport?