Why did Shopify start forcing automatic Checkout Extensibility upgrades starting January 2026 instead of leaving it opt-in indefinitely?

When did Shopify's automatic checkout upgrades start, and for which pages?

Shopify's automatic checkout upgrades came in three waves, and January 2026 was the second: the Thank you and Order status pages of Shopify Plus stores (Shopify Help Center, October 2026). The first wave, for the Information, Shipping and Payment steps of Plus stores still on checkout.liquid, the Plus-only checkout code file, began a year earlier. Which checkout surfaces each Shopify plan lost is answered separately, with every date by plan.

So January 2026 is the right date for the Thank you and Order status pages, and a year late for the checkout steps.

Why didn't Shopify leave the upgrade opt-in?

Shopify didn't leave the upgrade opt-in because it was ending support for checkout.liquid, and its first notice already promised automatic upgrades for the checkout steps. That February 2023 notice said checkouts not upgraded on time "will be automatically upgraded to an un-customized, out-of-the-box Shopify Checkout" (Shopify Changelog, October 2026).

Shopify's Plus upgrade guide, since retired, gave the reasons: checkout.liquid "has not been updated with new functionality since 2021" (Shopify Help Center, archived April 2025). Under version 4 of the Payment Card Industry Data Security Standard, it "is less secure than Checkout Extensibility", Shopify's app-based checkout (Shopify Help Center, archived April 2025). Shopify's Partners blog dates that version's effect to 31 March 2025 and singles out its new anti-skimming rules for payment pages (Shopify Partners blog, October 2026). Shopify's answer runs custom code only in sandboxes, walled-off environments apart from the checkout page, which it calls "a strict requirement of Shopify Checkout" (Shopify Partners blog, October 2026). So an indefinite opt-out would have kept uninspected code on the page those card rules target.

What did Shopify switch off before it upgraded a store?

Shopify switched off four things for Plus stores still on checkout.liquid, the Plus-only checkout code file, from 14 August 2024, months before any automatic upgrade (Shopify Help Center, archived April 2025):

1. Support. "Shopify won't provide customer support for updating or fixing checkout.liquid customizations on the Information, Shipping, and Payment pages."
2. Payment gateways. "The ability to deactivate payment gateways or switch providers is deactivated."
3. Fraud signals. "Accurate risk assessment becomes unreliable with unsandboxed code executing in checkout, so fraud indicators and recommendations in the admin aren't available for new orders."
4. Shopify Payments payout speed. "Because orders will be deemed as higher risk, payouts may be delayed by up to 5 days after a transaction is processed."

Read in order, the list is the argument. Shopify couldn't score fraud risk on a checkout running code it couldn't inspect, so it paid out more slowly against that checkout. That is why the upgrade stopped being optional.

What happened to a store on the day Shopify upgraded it?

Nothing visible broke on the day of an automatic upgrade: the checkout kept taking orders while its checkout.liquid customizations, the store's own checkout code, disappeared. Shopify's Plus guide said the checkout steps "will revert to a default state, losing all checkout.liquid customizations", and the store "will continue to process checkouts absent these customizations" (Shopify Help Center, archived April 2025). Brand settings from the theme editor carried over to the default checkout, but visual changes coded in checkout.liquid or its own script and style files "won't be loaded" (Shopify Help Center, archived April 2025).

On the Thank you and Order status pages, customizations using additional scripts, app script tags or checkout.liquid "will be lost" (Shopify Help Center, October 2026). Stores below Plus that missed 26 August 2026 "were upgraded automatically" (Shopify Help Center, October 2026). So the loss shows up in reports, not as an error: a field that stopped reaching the warehouse, or a conversion count that went flat. What the 26 August deadline did to reporting sets out the tracking check.

How much warning did Shopify give before forcing the upgrade?

Shopify gave 18 months of warning before the first deadline and almost two years before the first automatic upgrade (Deploi arithmetic from the dates below). The dates are public, so a store's exposure came from missed notices rather than a short runway.

• 13 February 2023. Shopify announced that checkout.liquid, the Plus checkout code file, would stop working on the checkout steps on 13 August 2024 (Shopify Changelog, October 2026).
• 14 August 2024. Support, payment gateway changes, fraud indicators and payout speed were restricted for stores that hadn't moved (Shopify Help Center, archived April 2025).
• 6 January 2025. Automatic upgrades began, each with "30-day notice by email" (Shopify Help Center, archived April 2025).
• 28 August 2025. Plus stores' deadline for the Thank you and Order status pages passed (Shopify developer docs, October 2026), and automatic upgrades followed in January 2026 (Shopify Help Center, October 2026).
• 26 August 2026. The deadline passed for every other plan, and Shopify upgraded the stragglers automatically (Shopify Help Center, October 2026).

Why some Plus migrations went smoothly and others did not turns less on this runway than on app vendors.