I changed the value for ConTeXt-Mark-version from "II" to "IV" in context.el file.
There are more than one such entry.
In the Windows platform, I added the following to the .emacs file:
(load "context.el" nil t t)
(add-to-list 'auto-mode-alist '("\\.tex\\'" . context-mode))
(eval-after-load 'tex
'(add-to-list
'TeX-command-list
'("LuaMetaTeX" "C:\\Users\\Leung\\AppData\\Local\\Programs\\ConTeXt\\tex\\texmf-win64\\bin\\mtxrun.exe --autogenerate --script context --autopdf %t"
TeX-run-command nil (context-mode) :help "Run LuaMetaTeX")))
Maybe it's similar in the OSX platform.