Adapting from v3/2.5 to v4


as you know version 4 released.but there is no enough documents for it.

I read “adapting from v3 to v4” developer document part,but I think it is not enough.

especially xml structure,folder structure are not clear.

can someone explain me folder structure for adaptation both frontend and backend?

can someone tell me folder,xml and more about addon adaptation?

best regards,