SmallCapsFeatures in XeLaTeX

On page 37 of my book on XeLaTeX I include the following example

 \newICUfeature{Contextuals}{Alts}{+calt}
 \setmainfont[Mapping=tex-text,Script=Greek,
 SmallCapsFeatures={Contextuals=Alts}]{Universal Modern}

This does not work anymore. One needs to modify this as follows:

 \setmainfont[Mapping=tex-text,Script=Greek,
   UprightFeatures={Contextuals=NoAlternate},
   SmallCapsFeatures={Contextuals=Alternate}]{Universal Modern}

If one omits the UprightFeatures part, then the SmallCapsFeatures apply everywhere.