After the 10.5 release I got the same report from client after client: the “Add to Cart” button sat disabled on variable products. The cause was a logic error rather than anything cosmetic, and for thousands of stores it switched sales off entirely. The WooCommerce 10.5.1 update is the cleanup.
There is nothing new in this dot release. It walks back some of the more aggressive changes 10.5 shipped: a script enqueuing conflict, Divi theme crashes, and some security hardening for legacy payment gateways.
The variable product “Add to Cart” gotcha
Most of the damage came from how 10.5 handled the wc-add-to-cart-variation script. Chasing a performance win, the core team disabled the “Add to Cart” button by default and left it to the script to re-enable. That works right up until you or your theme dequeue the script to run a custom variation handler, and then the button stays dead. The WooCommerce 10.5.1 update makes that logic more conservative.
// The logic now only disables the button if the script is actually detected
if ( wp_script_is( 'wc-add-to-cart-variation', 'enqueued' ) ) {
// Logic to manage button state safely
}If you were also fighting WooCommerce product permalink issues from 10.5, 10.5.1 at least gives you a stabler base for chasing down those leftover rewrite rules.
Fixing the Divi shop page blank-out
Divi users got hit hard by 10.5. Some of the new Shop page hooks threw PHP warnings that stopped products rendering at all when the Divi Builder was active. It is the familiar race condition, with the theme and the core plugin both reaching for the same global $product object. The team reverted those hooks to get compatibility back.
Hardening PayPal Standard callbacks
If you still run PayPal Standard, treat this one as mandatory. Shipping callbacks now carry token-based validation, which closes a man-in-the-middle style hole where someone could change a shipping address through an unauthorized callback mid-checkout. Everyone should be moving to REST-API based integrations anyway, but this keeps legacy stores safe in the meantime.
If this update is eating your dev hours, I can take it off your plate. I have been wrestling with WordPress since the 4.x days.
What to do about it
Don’t sit on this one. On 10.5.0 you are either losing conversions on variable products or carrying a PayPal security risk. Test on staging first and put the variation selection flow through its paces, watching for custom JS that collides with the new enqueuing checks.
