The following code is documented to change the numbering of the equations.

However, this still use numerals for the equations.

\setupformulas[conversion=characters]

\starttext

\placeformula[test]
\startformula E = mc^2 \stopformula

\stoptext

Is this a bug ? Is it the correct way to change the numbering ?

Any help is welcome. Thank you in advance,

Antoine C.