Hello,I'm also awaiting for this... Stable 10.3 fo Redmi 4X was released today/yesterday, and our rosy should be near.
BTW, do you know any official TWRP that supports Oreo encryption? I have one which seems to be a personal mod, but i'd prefer an official one (TWRP 3.3 doesn't decrypt internal nor data)
I do not know how to answer you, but surely someone will know.