I was very interested to see that WooThemes had written about the experience of the release of WooCommerce 2.4.
I had updated a custom theme that used variations for subscription products. This particular site had started on WooCommerce before 2.0 and had undergone various upgrades, including, of course, the WooCommerce data. So what happened?

The variation combinations kept giving the error message “Sorry, no products matched your selection. Please choose a different combination.” I contacted WooThemes support and they looked into the problem. The issue was fixed in version 2.4.4 and according to the change log they fixed “Ajax variation handling when ‘any’ attribute is set”. However, for the fix to actually work, I still needed to re-save the product after updating the plugin and running the WooCommerce database updater. While this was trivial with only one product, it would have been troubling with a lot of them. In any case, I am happy to have the fix and to be able to update the site to the latest version.