Consider the following example \definefontfeature[capital spacing] [cpsp=yes] \definefontfeature[small capitals] [c2sc=yes] \starttext \setfontfeature{capital spacing} % not OK % \setfontfeature{small capitals} % OK ABCDEFGHIJKLMNOPQRSTUVWXYZ \stoptext It works okay with small capitals but with capital spacing the context throws an error: …/node-inj.lua:70: attempt to index local 'spec' (a nil value) Greeting Andreas