---
title: "Shopify UI extensions need API version 2026-01 or later to deploy after October 1; bundle size exceptions: 2026-10-01 | Harbyn"
description: "Shopify UI extensions need API version 2026-01 or later to deploy after October 1; bundle size exceptions, effective Oct 1, 2026."
canonical: "https://harbyn.com/changes/shopify/2026-09-17-request-a-bundle-size-exception-for-existing-ui-extensions"
last-updated: 2026-09-29
---

# Shopify UI extensions need API version 2026-01 or later to deploy after October 1; bundle size exceptions

Markdown version of <https://harbyn.com/changes/shopify/2026-09-17-request-a-bundle-size-exception-for-existing-ui-extensions>.

Deprecation - Shopify. medium severity. In effect.

To remain deployable after October 1, 2026, every existing UI extension must use API version 2026-01 or later. Extensions on 2025-10 or later are limited to a 64 KB compressed bundle (128 KB for full page customer account extensions); if still over after optimization, request an exception with the minified bundle and esbuild metafile.

The deadline passed on Oct 1, 2026.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Shopify](https://harbyn.com/vendors/shopify.md) |
| Kind | Deprecation |
| Severity | medium |
| Status | In effect |
| Announced | Sep 17, 2026 |
| Effective | Oct 1, 2026 |
| Added to Harbyn | Sep 29, 2026 |
| Lead time | 2 days of warning |
| API versions | `2025-10` |
| Vendor page | <https://shopify.dev/changelog/request-a-bundle-size-exception-for-existing-ui-extensions> |
| Review | Reviewed by a person, extracted by a deterministic parser |

## Find it in your code

```sh
npx harbyn scan
```

The scanner reads your repository on your machine and reports every file and line that uses the identifiers above. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://shopify.dev/changelog/feed.xml> (changelog, fetched 2026-09-29 02:31 UTC, sha256 `cffd0e2982368954baa11898a7f99a4fc4032b50b36c6137b67385ebc4443f58`)

## Related changes

### More from Shopify

- [Removed session.currentSession.staffMemberId from POS UI Extensions (2026-10)](https://harbyn.com/changes/shopify/2026-09-17-removed-session-currentsession-staffmemberid-from-pos-ui-extensions-2026-10.md) (Breaking change, announced Sep 17, 2026)
- [Updates to Events payloads and subscription configuration](https://harbyn.com/changes/shopify/2026-09-16-updates-to-events-payloads-and-subscription-configuration.md) (Breaking change, effective Sep 16, 2026)
- [The automaticDiscounts query is removed in API version 2027-01](https://harbyn.com/changes/shopify/2026-09-18-the-automaticdiscounts-query-is-removed-in-api-version-2027-01.md) (Retirement, announced Sep 18, 2026)
- [family\_name is optional for B2B orders in Payments Apps API requests](https://harbyn.com/changes/shopify/2026-09-15-family-name-is-optional-for-b2b-orders-in-payments-apps-api-requests.md) (Behavior change, announced Sep 15, 2026)

### Changes at other vendors

- [AWS Lambda: Python 3.10 runtime deprecation](https://harbyn.com/changes/aws-lambda/2026-10-08-python-3-10-runtime-deprecation.md) (effective Oct 31, 2026)
- [Jira / Atlassian Cloud: Atlassian Analytics dashboard subscriptions being removed](https://harbyn.com/changes/atlassian-jira/2026-08-10-atlassian-analytics-dashboard-subscriptions-being-removed.md) (effective Nov 2, 2026)
- [Google Cloud Run and Functions: .NET 8 runtime deprecation](https://harbyn.com/changes/google-cloud/2026-10-08-net-8-runtime-deprecation.md) (effective Nov 10, 2026)
- [GitHub: X-GitHub-Stateless-S2S-Token header ignored from 2026-11-30](https://harbyn.com/changes/github/2026-10-02-x-github-stateless-s2s-token-header-ignored-from-2026-11-30.md) (effective Nov 30, 2026)

[All upcoming deadlines](https://harbyn.com/deadlines.md)