I tried to look at a font and enabled the trackers like this \enabletrackers[*] \definefont [test][name:texgyreheros] \starttext abcäöü \stoptext The context compilations fails then with ...ext/tex/texmf-context/tex/context/base/mkiv/font-oup.lua:718: attempt to call a nil value (global 'report_unicode') Imho around a week ago (when I asked about the source han font) this worked. -- Ulrike Fischer https://www.troubleshooting-tex.de/