Support will continue for the Vox from what they say:
http://www.kobo.com/koboarc/support/
1. Can I upgrade my Kobo Vox to the Kobo Arc?
Unfortunately, the breakthrough Tapestries user experience and Discovery technology are highly integrated into the Kobo Arc hardware and software.
However, we are committed to supporting the Kobo Vox and will be delivering many new feature enhancements over the coming year.