There are plenty of nuclear experts who analyze nuclear policy, nuclear force composition and other aspects for a living. If China implements such a policy. They will clearly know about it and release their finding. There are annual report of such things.Right, let me just call my CMC friend real quick and see if he can get you a live tour.
I suggest you one such expert Podcast I listened to recently in Sinica.
Based on several such expert reports, my understanding is that China is exploring nuclear doctrine changes including launch on warning, and also abandoning no first use, but they have not changed their doctrine yet.