However, a few unicode characters desapear or cause small problems, like these (unicodes between 2012 and 2015):
They work here both in mkii and mkiv (...) Does it make any difference if you replace the font in TeX tree with the font downloaded straight from SIL (and maybe regenerate font cache for luatex just in case)?
Here is md5sum of gentium files. However, I wasn't able to get those characters with any font. My first tought was that input could be in something different from utf8, but I can get the ellipsis from the example below to work. 34cc1c1f334221ba0b67e05011036906 *context/tex/texmf/fonts/truetype/public/gentium/GenI102.TTF c8b88a8ecf5f6f93052fb2d1628438d5 *context/tex/texmf/fonts/truetype/public/gentium/GenBasBI.ttf c968d72c4bfc649e2581a5d6699fd31f *context/tex/texmf/fonts/truetype/public/gentium/GenR102.TTF 03ca29844a7db9b018b2dd4de50be6d6 *context/tex/texmf/fonts/truetype/public/gentium/GenBasB.ttf
You'll probably need to post a minimal complete example that fails.
Here it is. The ellipsis is okay in the output. The horizontal bars, however, just desapear, although they do use some space, as the first letters do not stay aligned with the last line. %%%% \enableregime[utf] \usetypescript[gentium] \setupbodyfont[gentium,20pt] \starttext ― Tá vendo? Você não entende! ― Claro que entendo… This is a line without a dash. \stoptext