tried to fix `README_NEXT.MD` to `README_NEXT.md` but suffix is not recognised by git so rename README_NEXT.MD to README_PART2.md.
I'll write two articles based on that content you can see already (because you follow the Iris project in github)
Former-commit-id: 48bb828909a9bd72939a6de3ee325d15dbb9f88b