---
title: "HubSpot Legacy APIs and Apps: What's Going Unsupported and When: 2027-09 | Harbyn"
description: "HubSpot Legacy APIs and Apps: What's Going Unsupported and When, effective Sep 2027."
canonical: "https://harbyn.com/changes/hubspot/2026-09-15-legacy-apis-and-apps-what-s-going-unsupported-and-when"
last-updated: 2026-09-29
---

# HubSpot Legacy APIs and Apps: What's Going Unsupported and When

Markdown version of <https://harbyn.com/changes/hubspot/2026-09-15-legacy-apis-and-apps-what-s-going-unsupported-and-when>.

Deprecation - HubSpot. high severity. Announced. Upcoming.

HubSpot ends support for v1-v3 API endpoints, legacy public apps and legacy pre-Projects private apps, with enforcement in September 2027. After that, apps calling v1-v4 APIs lose certification and apps on the legacy architecture can be delisted; migrate directly to date-based versioning and Projects-based apps. v4 support ends separately on March 30, 2027.

About 311 days left: the deadline is Sep 2027 (the vendor named the month, not the day).

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [HubSpot](https://harbyn.com/vendors/hubspot.md) |
| Kind | Deprecation |
| Severity | high |
| Status | Announced |
| Announced | Sep 15, 2026 |
| Effective | Sep 2027 (month only; the vendor gave no day) |
| Added to Harbyn | Sep 29, 2026 |
| Lead time | 337 days of warning |
| Vendor page | <https://developers.hubspot.com/changelog/legacy-apis-and-legacy-apps-whats-going-unsupported-and-when> |
| Review | Reviewed by a person, extracted by a deterministic parser |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses HubSpot, from its packages and API hosts. 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://developers.hubspot.com/changelog/rss.xml> (changelog, fetched 2026-09-29 02:31 UTC, sha256 `fb63ff288927e6e25ccc3ab3af7af0ec96c493cb7950f85d857ce014493dea48`)

## Related changes

### More from HubSpot

- [End of Developer CLI support for Node.js 20](https://harbyn.com/changes/hubspot/2026-10-19-upcoming-sunset-end-of-developer-cli-support-of-node-js-20.md) (Retirement, effective Jan 8, 2027)

### 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)