August 28, 2026: The Day Shopify Rewrites Every Non-Plus Checkout

What Is Actually Happening

Shopify has been migrating checkout customization from a legacy system (checkout.liquid and Additional Scripts) to a new system (Checkout Extensibility — UI Extensions, Web Pixels, and Functions) for over two years. Plus stores completed this migration earlier. Now it’s everyone else’s turn.

On August 28, 2026, Shopify will auto-upgrade every non-Plus store. This means:

• Any custom code in checkout.liquid will be removed
• Any scripts in “Additional Scripts” (Settings → Checkout → Order status page → Additional scripts) will stop executing
• Any script tags on the Thank You and Order Status pages injected by apps will be removed
• Your checkout will use the new Checkout Extensibility system exclusively

This affects stores on Basic Shopify ($39/mo), Shopify ($105/mo), and Advanced ($399/mo). If you’re on Plus, this already happened to you earlier.

What Breaks (The Specific List)

The Biggest Gotcha: Non-Plus Stores Can’t Customize Most Checkout Steps

This is the part nobody talks about. While the migration to Checkout Extensibility is mandatory for everyone, the actual customization capabilities depend on your plan:

If you previously had custom logic on the Information, Shipping, or Payment steps — like custom fields, address validation, or conditional payment methods — you need to either upgrade to Plus or find an alternative approach (Shopify Functions may handle some of these cases).

The Migration Checklist (Do This Before August 28)

Step 1: Audit What You Have (10 minutes)

1. Go to Settings → Checkout in your Shopify admin
2. Look for a yellow banner about checkout upgrade — if you see it, you have legacy customizations
3. Go to the Script Editor app (if installed) — review any remaining scripts
4. Copy ALL content from “Additional Scripts” into a text file — you’ll need this reference

Step 2: Migrate Tracking Pixels (20 minutes per pixel)

1. Go to Settings → Customer Events
2. Click “Add custom pixel”
3. Choose your platform (Meta, Google, TikTok, etc.) or “Custom” for anything else
4. Paste your pixel code into the sandbox — Shopify validates it before going live
5. Test with the built-in pixel tester

Google Tag Manager users: s: Shopify now has a native GTM connector. Settings → Customer Events → Add pixel → Google Tag Manager. Paste your container ID. Done. Takes 3 minutes.

Step 3: Migrate Post-Purchase Content (15 minutes)

1. Go to Settings → Checkout → Checkout Editor
2. Customize your Thank You and Order Status pages using the drag-and-drop editor
3. Add any custom content, banners, or messages

Step 4: Test With Real Orders (Essential)

1. Place a real test order through your store
2. Open your ad platform (Meta Ads Manager, Google Ads) and verify the conversion event fired
3. Check Google Tag Manager preview mode for all tags
4. Wait 24 hours — verify the conversion data appears in your reports

Do NOT skip testing. g. Multiple merchants who went through the Plus migration reported that pixels appeared to fire in test mode but failed silently with real orders. Test with actual money. Place a $1 order and refund it. This is the only way to be sure.

What Happens If You Miss the Deadline

Shopify will auto-upgrade your checkout on August 28. Your store will continue processing orders. But:

• All tracking pixels stop firing → ad platforms lose conversion data → ROAS drops because algorithms can’t optimize
• Affiliate attribution breaks → partners don’t get credit → they stop promoting your products
• Post-purchase upsells disappear → average order value drops
• Custom Thank You page content is replaced with Shopify’s default

You won’t see an error message. Your orders dashboard will look normal. Revenue might even look fine for a few days — until ad performance degrades from missing conversion data. This is a silent failure that takes weeks to show up in your metrics.

The Good News

For most stores, the migration is actually an upgrade. The new system is faster (server-side, no render-blocking scripts), more secure (sandboxed), and upgrade-safe (won’t break when Shopify updates). The migration work is mostly about moving pixels, which takes under an hour for a typical store.

The stores that should be worried are ones with heavy checkout customization — custom fields, multi-step flows, complex upsells, unique shipping logic. If your checkout is relatively standard (tracking pixels + maybe a post-purchase offer), this is an afternoon of work.