On 28th August 2025, Shopify officially switched off legacy customisations on the Thank You and Order Status pages. This was a major milestone in their ongoing transition to Checkout Extensibility: a modern, app block based system that promises improved speed, security and flexibility.

For many merchants, this update may have passed quietly in the background. But for those with custom scripts, tracking codes or personalised checkout flows built using checkout.liquid or the Additional Scripts box, the impact could have been immediate and, in some cases, disruptive.

What Actually Changed?

Before 28th August:

– Merchants could insert custom tracking scripts (Facebook Pixel, Google Ads conversion tags, affiliate tracking).
– Developers could add personalised messaging, upsell prompts or styling changes directly via checkout.liquid.
– Some third party apps relied on script tags to display dynamic elements post checkout.

After 28th August:

– All of the above is now disabled or uneditable.
– Any custom code added in legacy ways has effectively stopped working.
– Shopify now requires merchants to use the Checkout Extensibility framework (blocks, app pixels, functions, post purchase extensions).

The Potential Impact on Your Store

To put it into context, here are a couple of real world style examples of how this change could affect businesses:

Example 1: Tracking Lost Overnight

A fashion retailer was running a Facebook Ads campaign driving thousands of visitors. Their old setup relied on a script in the Additional Scripts section to pass purchase values back to Facebook. On 29th August, their conversions stopped tracking. Ads Manager showed no sales, even though orders were being placed. Within days, their campaign performance collapsed, as Meta’s algorithm didn’t know who was buying.

Example 2: A Broken Upsell Flow

A nutrition brand used a customised Order Status page to show a “Buy Again with 10% Off” button. This was built into checkout.liquid. Post deadline, the upsell vanished. Overnight, they lost a key revenue stream that was previously generating 15% of monthly sales.

These are not hypotheticals, they’re scenarios I’ve seen across the Shopify ecosystem when platform updates remove legacy support.

The Pros of Checkout Extensibility

It’s not all bad news. Shopify’s update has some real positives:

– Improved Security & Reliability:
Removing open script areas reduces the risk of vulnerabilities, broken code or malicious injections.
– Faster Checkout Performance:
Shopify has optimised Extensibility to be faster and more consistent across devices. A leaner checkout means better conversion rates.
– Future Proofing:
Checkout Extensibility is the framework Shopify is investing in. Migrating now ensures your store is aligned with future updates.
– App Ecosystem:
Instead of custom hacks, you can now leverage approved app integrations for pixels, post purchase offers and personalisation.

The Cons & Challenges

Of course, there are downsides too:

– Migration Costs:
If your business invested heavily in custom scripts, you’ll need developer support to rebuild functionality using the new system.
– Feature Gaps:
Not every feature that was possible with checkout.liquid is yet available in Extensibility. Some merchants may lose niche but valuable features.
– Tracking Headaches:
For businesses reliant on custom tracking setups, moving to app pixels requires careful re-implementation and testing.
– Learning Curve:
For smaller teams without technical support, the shift feels daunting. It’s no longer a case of pasting in a script; it requires proper setup.

What You Should Do Next

– Audit Your Checkout Setup: If you had any custom scripts, pixels or design changes, check if they’re still firing.
– Rebuild in Extensibility: Use Shopify’s blocks, pixels and apps to replicate your old setup.
– Test Everything: Ensure your tracking, upsells and customer flows are working.
– Seek Expert Support: If you’re unsure where to start, don’t leave it to chance to get help.

Final Thoughts

Shopify’s August 28th change is a reminder of one key truth in eCommerce: platforms evolve and merchants must evolve with them. While these changes may feel disruptive in the short term, they ultimately pave the way for a more robust and scalable checkout experience.

But ignoring the update isn’t an option. If your scripts have stopped working, you could already be losing sales, data and marketing visibility without realising it.

Thanks for reading and if you need any help or Shopify support then please feel free to reach out to me.

Myk Baxter
eCommerce Expert