# The FHIR DSTU 2 API stops working

Calls to /dstu2/* on Oracle Health Millennium FHIR APIs stopped working on December 1, 2025.

On December 1, 2025, the FHIR DSTU 2 API will stop working. All calls to /dstu2/* endpoints will fail after this date. Oracle Health Millennium FHIR APIs is replacing this functionality with the R4 version.

## What to use instead

Call the FHIR R4 APIs under /r4/{tenant}/ instead of /dstu2/{tenant}/. Migrating requires updating your resources to R4 rather than only changing the endpoint path.

- API: Oracle Health Millennium FHIR APIs (fhir-ehr.cerner.com)
- Kind: Version retirement
- Takes effect: December 1, 2025
- Calls after that day: fail
- Calls it hits: `/dstu2/*`
- Source: [Announcement](https://docs.oracle.com/en/industries/health/millennium-platform-apis/mfdap/dstu2_overview.html)
- Verified: October 26, 2026, against Oracle Health Millennium FHIR APIs's own pages
- Page: https://www.okapi.bot/providers/oracle-health-millennium-fhir-apis/breaking-changes/the-fhir-dstu-2-api-stops-working/

## Oracle Health Millennium FHIR APIs's words

> As of December, 2025, Oracle will no longer support DSTU 2 FHIR APIs. For more information, see the FHIR DSTU2 End of Support announcement on the Oracle Health Developer Forums. This functionality is replaced by the R4 version. Update your applications to use R4 before December to prevent interruptions to service.

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent