In the latest beta (ConTeXt  ver: 2014.11.04 19:10 MKIV), when I run

\definefallbackfamily[mainface][serif][IFAO Grec Unicode]
[range={02BB-F8FF,10140-1D513},
protrusion=quality,
expansion=quality,
mode=node,
  kern=yes,
force=yes,
check=no,
rscale=0.95]

\setupbodyfont[mainface,10pt]

\definefont[Greek][IFAO-Grec at 10pt]

\starttext
 ἔφεϲιϲ and τελειότηϲ

 {\Greek ἔφεϲιϲ and τελειότηϲ}
\stoptext

the fallback Greek does not display. All I get is:

    and
 ἔφεϲιϲ and τελειότηϲ

This definition of \definefallbackfamily used to work. Has there been a
change in the font mechanism?

Alan