After updating to wc 2.1 (including database update) I saw two error rows on product pages, containing Failed to open stream ... wc-core-functions.php on line 100.
Also the update adds different things I don't want, like a 'buy' button, a stock indication, etc. I removed them in the previous woocommerce version.
Using Elegantthemes Foxy theme. Example page.
I re-installed an older version of wc to keep the site running correctly. Please fix this!