Recent changes to X1 and x2 visas

Hello
I am in China on a 30 day tourist (L) type. I want to study in Kunming for 3 months. I just discovered that the student (X) type regulations changed on 9 October 2017. But I don't know how they have changed. I have received conflicting advice from the language schools that I have spoken to.
Can someone pls advise on the new distinctions between X1 and X2 type? In particular, I'd like to know for how many month each one is valid and whether I need to leave the country to apply for either of them.
Many thanks