Updated September 11, 2026. Dates are as published in Shopify's developer changelog entry of August 24, 2026. Third-party products are named to identify them only.
An agency that builds Shopify stores carries the ScriptTag deadline across every client at once: Shopify stops accepting script tag create and update calls on October 1, 2026 and stops running the existing tags on March 1, 2027, and a client who loses a storefront feature in March will ask the agency first. The checklist below takes a roster from "we think we are fine" to a dated record per client, in an afternoon for most agencies.
Background on the two dates is in Shopify ScriptTag Deprecation: What Stops on October 1, 2026 and March 1, 2027. The free outside check used in step 2 is at index.statusbird.io/october-1.
1. Write down the roster, including stores you no longer maintain
List every client storefront the agency built or manages, with the live domain. Include stores on a maintenance retainer, stores that were handed off, and stores in the portfolio section of your own website. The handed-off ones matter most: nobody else is checking them, and your name is still attached to them publicly.
2. Check each storefront from the outside
For each domain, run the free check. It fetches the homepage once and reports any script loaded through Shopify's ScriptTag API, with the app named where the script host is known. Three outcomes are possible for each store:
- Clear. No legacy script tag on the homepage.
- Cleanup only. An app's theme app extension is present and an old tag remains. Nothing breaks in March; the vendor should remove the leftover tag.
- At risk. An app loads only through a legacy tag. Its storefront feature stops on March 1, 2027.
The homepage is one page type. Apps that inject only on product, collection, cart or search templates are not visible from it, so treat a clear homepage as necessary, not sufficient, and check the other templates for stores where the app mix is unknown.
3. Keep a dated record per store
Storefronts change. A store that is clear in September can install a script tag app in October, and a store flagged in September can be fixed by November. Record the domain, the date, the result and the app names in one place, so that when a client asks in March you can show what was true and when. A screenshot of the check result with the date visible is enough; a one-page PDF per store is better because it can be forwarded as is.
4. Send each at-risk vendor one question
The only question that matters is the release date of the vendor's theme app extension, and whether the update removes the old tag. Send it from the client's account or with the client copied. A vendor with a date and a published migration notice is fine. A vendor with neither is a replacement decision, and after October 1 a replacement that still uses script tags cannot install itself, so that decision belongs in September.
5. Tell clients before they find out
A short note to every client, whatever the result, does two things: it shows the agency checked before being asked, and it sets the March 1, 2027 date in the client's calendar rather than yours. For clear stores, attach the dated record. For at-risk stores, attach the record and the vendor's answer, and propose the swap if there is no migration date.
6. Show the clean result
An agency whose whole roster checked clean has a fact worth stating publicly. The October 1 Index issues a verification page and a badge for portfolio records, and lists agencies with clean portfolios for merchants who arrive at the index needing a migration done. Both are free; the listing is a statement of one check on one date, not an endorsement.
7. Put the deadline where you will see it
Add March 1, 2027 to the agency calendar with a reminder in early February to re-run the check on every at-risk store. If your agency publishes a blog or a client newsletter, the index has an embeddable countdown that updates itself.
Frequently asked questions
Do we need to check stores we no longer maintain?
If the store is in your public portfolio or a client could reasonably call you about it, yes. The check is free and takes seconds per store, and an outside check does not require access to the store's admin.
What if a vendor says it has migrated but the check still shows a legacy tag?
That is the cleanup-only case: the extension is present and the old tag was never removed. Nothing breaks in March, but ask the vendor to remove the tag so the store's source is clean and future checks are unambiguous.
Can we do all of this from the Shopify admin instead?
The admin lists installed apps but does not show which loading mechanism each one uses on the storefront. An outside check of the rendered page is the direct way to see it, and it is the same view a shopper's browser gets.
How often should stores be re-checked?
Once now, once after each at-risk vendor reports a migration, and once in February 2027 for every store that was ever flagged. Stores with frequent app changes deserve a monthly check.
Where do the dates come from?
Shopify's developer changelog entry of August 24, 2026: create and update calls return errors on October 1, 2026 on every API version, and injection into storefronts stops on March 1, 2027.
Start with step 2: check any client storefront free at index.statusbird.io/october-1. The October 1 Index is an independent research service of StatusBird LLC.
StatusBird LLC is not affiliated with, endorsed by or sponsored by Shopify Inc. Shopify, Shopify Plus and Shopify App Store are trademarks of Shopify Inc. App names are used to identify the products only. The October 1 Index is an independent research service of StatusBird LLC and is not a Shopify app.