Hi, [sorry, I know it's the wrong list, but I'm not subscribed to ntg-context] I think line 144 in l-math.lua should read function math.ult(m,n) otherwise, the function math.tointeger would be overwritten with older luatex versions. (reference: https://source.contextgarden.net/tex/context/base/mkiv/l-math.lua ) Best, -- Robert