# HubSpot for Developers Breaking Change: CRM API Write Validation Enforcement Starting with the 2026-09 API Version

- Product: HubSpot for Developers (https://whatsnew.fyi/product/hubspot-developers)
- Vendor: HubSpot
- Date: 2026-08-11
- Original notes: https://developers.hubspot.com/changelog/crm-api-write-validation-enforcement
- Permalink: https://whatsnew.fyi/product/hubspot-developers/releases/2026-08-11-breaking-change-crm-api-write-validation-enforcem

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Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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Starting with the /2026-09/ API version shipping on September 8, 2026, HubSpot will enforce admin-configured validation rules on all CRM API write paths. If your integration creates or updates CRM rec…

- **changed** — CRM API write paths will enforce admin-configured validation rules starting with the /2026-09/ API version on September 8, 2026