[NTG-context] new way to do \addff?

Hello, \addff (and \doaddfeature) no longer seem to work. What's the alternative to add/remove features on the fly? MNWE: === \starttext \startluacode fonts.handlers.otf.addfeature{ name = "fanum", type = "substitution", data = { [0x30] = 0x41 -- '0' => 'A' } } \stopluacode \definefontfeature[fanum][fanum=yes] {0123 %\addff{fanum} \doaddfeature{fanum} 0123 %% does not work \definedfont[dejavusans*fanum] 0123 %% works } 0123 \stoptext ===