If your ExpressionEngine website includes an online store, there is a good chance it runs on CartThrob. CartThrob is the eCommerce plugin that powers purchasing, order management, and payment processing on ExpressionEngine sites. Version 9.0.0 has just been released, and while the announcement is aimed at developers, the implications are squarely about how your store operates.
Here is what you need to know.
CartThrob handles the commercial layer of your ExpressionEngine site: product listings, the shopping cart, checkout, payment gateway connections, order notifications, and inventory tracking. If customers can buy something on your site, CartThrob is almost certainly involved. Like any piece of software your site depends on, keeping it current is part of keeping your store reliable.
The most significant change from a business operations standpoint is payment gateway reliability. Version 9 updates the connection endpoints for Opayo and Elavon, two payment gateways used by many UK-based stores, and extends Stripe payment intents to include complete order details. Authorize.net error messaging has also been improved. These are not cosmetic changes. A payment gateway that is connecting to an outdated endpoint is a gateway that can fail at the moment a customer tries to pay. Getting this right is basic operational hygiene.
Alongside that, CartThrob 9 now runs inventory checks before the checkout form is rendered. Previously, a customer could reach the checkout stage on a product that had already sold out. Now that check happens earlier in the process, before the customer has committed time and information. That reduces failed transactions and the frustration that comes with them.
Order management has also been improved: the Order Manager interface is updated, notification emails are more reliable, and status change emails, which had been failing in certain scenarios, now send correctly. For a business processing orders day to day, these are the kinds of fixes that make the difference between a store that runs smoothly and one that needs constant monitoring.
CartThrob 9 is compatible with PHP 8.1 through 8.3. This matters because PHP versions follow a support lifecycle, and running on an outdated PHP version means running on infrastructure that no longer receives security updates.
PHP 8.3 is the current maintained version. If your server is running an older PHP version, your hosting environment is already in a risk position regardless of what software sits on top of it. A CartThrob upgrade is often the prompt that surfaces this question: what PHP version is your site actually running on? If you do not know the answer, that is worth finding out.
Existing CartThrob customers have 45 days from the release of version 9 to upgrade at a discounted price. After that window, the standard pricing applies. The upgrade also extends your renewal period by one year from the purchase date, covering ongoing updates and support.
If you are on CartThrob 8 and your store is active, the 45-day window is a practical reason to move sooner rather than later. If you are on an older version still, the path is the same but may require a staged upgrade depending on how your site is configured.
If your ExpressionEngine store is running CartThrob 8, upgrading to version 9 is straightforward and the discounted window makes now the right time to do it. The payment gateway updates alone are reason enough if your store uses Stripe, Opayo, Elavon, or Authorize.net.
If you are not sure which version of CartThrob your site is running, or whether your payment gateways are connecting correctly, that is exactly the kind of thing a CartThrob-experienced developer should be able to tell you in short order.
If you are running an older version of CartThrob or an older version of ExpressionEngine alongside it, the upgrade path needs more planning. Jumping straight to CartThrob 9 without first establishing where your ExpressionEngine installation stands is not advisable.
The most useful first step is understanding where your store sits: which version of CartThrob, which version of ExpressionEngine, and which PHP version on the server. Those three answers determine how straightforward your path to CartThrob 9 is.
If you would like us to check and advise, that is something we can turn around quickly. Get in touch.
Related Services
There’s no single answer to when you should upgrade your ExpressionEngine installation, but there are several clear signals that tell you it’s overdue. Most business owners don’t think about this until something goes wrong. By then, the upgrade is usually more involved than it would have been if it had been done earlier.
PHP 8 is now the standard version running on most web hosting infrastructure. Many ExpressionEngine sites were built when PHP 7 was current and have never been reviewed for PHP 8 compatibility. If nobody has mentioned this to you, there is a reason for that, and it is worth understanding.
Most clients come to us when their site has started to feel like a risk rather than an asset. Whether the agency relationship has ended, an upgrade has been delayed, or the site has simply grown beyond what it can handle, a conversation costs nothing.
Get in touch with KarlTrusted by established businesses and growing brands across the UK
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Karl is the founder of Expression 37 Ltd and has been working exclusively with ExpressionEngine and Craft CMS since 2007. In eighteen years he has supported more than 80 clients across the UK, from long-term retainer arrangements to emergency rescues when something has gone wrong at the worst possible moment. Every piece of work is handled personally by Karl, with no account managers or junior developers between you and the person doing it.
Find out how we workThornfields has relied on Expression 37 for our ExpressionEngine website for a number of years now, and the level of service has consistently been excellent. The site is central to how we promote our training programmes, so reliability matters a great deal to us. Any issues are dealt with quickly, updates are handled without disruption, and Karl takes the time to understand what we actually need rather than just applying a generic fix. We would not hesitate to recommend Expression 37 to any organisation that needs a genuine specialist looking after their site.
Chris Ibbetson, Head of Training
Thornfields Primary Care Training