[NTG-context] Fwd: Oldstyle numbers

I’m new to ConText and so my question may be a stupid one. But I hope somebody can help me: How can I activate »old style numbers« (Medievalziffern). I thought, it should work like this: \setupbodyfont[palatino, 10pt] \definefontfeature [default] [default] [onum=yes] But this doesn’t work. What do I have to do? Many thanks for your help!