Fatal Error WC_ATTRIBUTE_LABEL() after upgrade to 2.0.2

Hello.
I did an upgrade to the last available version of the theme (2.0.2), and now, when I go to the page of the single product I have this error in the middle of the page, instead of options to select:

fatal error: call to undefined function wc_attribute_label() in /home/mhd-01/www.mydomain.com/htdocs/wp/wp-content/themes/virtue/woocommerce/single-product/add-to-cart/variable.php on line 23

I tried to return to the precedent version I was using (2.0.0) and all is ok again.
What’s the issue and how can I resolve it?

Thank you.