I want to know if it's possible use HarfTeX/LuaHBTeX with ConTeXt (MKIV), mainly for what can be done with them (the "mode=harf" feature and Lua language features). Although this is pretty easy with LaTeX: \usepackage{harfload} \setmainfont{font}[RawFeature={mode=harf}] I have no idea of how to make it work with context. I've tried the following with a test file (a simple \starttext .. \stoptext document): context tests.tex --engine=luahbtex And this happens: mtx-context | run 1: luahbtex --fmt="/home/coragyps/.texlive2019/texmf-var/luatex-cache/context/a86c089b384a3076dc514ba966a1fac9/formats/luatex/cont-en" --jobname="tests" --lua="/home/coragyps/.texlive2019/texmf-var/luatex-cache/context/a86c089b384a3076dc514ba966a1fac9/formats/luatex/cont-en.lui" --c:currentrun=1 --c:engine="luahbtex" --c:fulljobname="./tests.tex" --c:input="./tests.tex" --c:kindofrun=1 --c:maxnofruns=9 --c:texmfbinpath="/usr/local/texlive/2019/bin/x86_64-linux" "cont-yes.mkiv" This is LuaHBTeX, Version 1.11.2 (TeX Live 2020/dev) system commands enabled. (Fatal format file error; I'm stymied)mtx-context | fatal error: return code: 256 What should I do? Thank you in advance