Is there an official announcement from People's Bank of China to state that banks can deal with bitcion now?
I don't think so - but you can now find links in BTCC to inject funds from banks (which has not been possible since the boom in 2013).
This is the way that things are done in China (never really officially endorsed but without a doubt the central government is 100% aware of it).
If the government gets "spooked" by another massive bubble then I'd expect those funding links will disappear (as they did in 2013).