Didn't found anything about this, so: I would appreciate having support for old style figures as found in OpenType fonts.

Besides this I am really looking forward to have Prince 7 because of its support for OpenType!

We've experimented with allowing the activation of arbitrary OpenType features using the font-variant CSS property, and we may add keywords for some commonly used features.

A beta version of Prince 7.0 is available now, and we have extended the font-variant property with a new value, prince-opentype(), which can be used to apply arbitrary features. For example:

span { font-variant: prince-opentype(dlig, onum) }

This is still experimental, but there is interest in the CSS community to extend the support for such features in the future.

Five years later, I'm very happy this works! Thanks.