Restoring broken checkouts on two stores after their cart lost support

The challenge

An Australian web and design agency looked after Joomla stores that relied on the same shopping-cart extension. After the extension's developer ended support, checkouts on two of these stores began to fail and no fixes were coming from the vendor.

On the first store, changing the country did not reload the list of states or zones, and logged-in customers could not continue past the billing-address step. On the second store, which had been upgraded to Joomla 4, the checkout and quick-registration flow failed, and enabled shipping methods had disappeared from the admin panel, making them impossible to manage. The agency needed someone who could work directly in the unsupported cart's code.

What we did

• Diagnosis in unsupported code. We traced each failure to the cart extension's checkout code rather than relying on a vendor update that would not arrive.
• Zone and billing fixes. On the first store we repaired the country/zone reload and the logged-in billing-address continue step, so returning customers can complete checkout.
• Checkout and registration fix. On the second store we fixed the checkout and quick-registration process for new customers.
• Admin shipping methods. We resolved the bug hiding enabled shipping methods in the second store's admin, so the team can manage delivery options again.
• Transparent hand-over. We supplied the agency with the paths of every file we changed, so future maintenance or updates can account for the fixes.

Tech stack

PHP, Joomla 4, J2Store