I installed WooCommerce 18.104.22.168 and couldn't anymore add Product Categories. When I tried to add a new category I got the following error:
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 19456 bytes) in /public_html/wp-content/plugins/woocommerce/admin/writepanels/writepanels-init.php on line 212
Before that I got another error from /plugins/woocommerce/admin/writepanels/writepanels-init.php on line 55, which I managed to resolve by disabling SKUs from the WooCommerce settings.
Only solution for me was to downgrade back to WooCommerce 1.3.2, which resolved all these problems.