To prevent disruption when Salesforce ends support for API traffic that uses an incorrect instanced URL, make sure that API traffic to your org uses the org’s My Domain login URL. First available in Summer ’25, this release update was scheduled to be enforced in Spring ’26, but we postponed the enforcement date to Spring ’27.
Where: This change applies to Lightning Experience and Salesforce Classic (not available in all orgs) in all editions except Database.com.
When: This update is postponed to Spring ’27. Salesforce enforces this update in phases. For specific enforcement dates, see End-of-Support Schedule for Incorrect Instanced URLs in API Traffic.
Why: Salesforce is decommissioning the service that supports hard-coded references to an incorrect instance name in API application traffic routing. When you use your My Domain login URL for API traffic, that login method continues to work after your org is moved to another Salesforce instance. Also, because My Domain names are unique, requiring your org’s My Domain login URL adds another layer of security.
How: Replace instanced URLs in your API calls with your My Domain login URL.
To test this change, from Setup, in the Quick Find box, enter My Domain, and then select My Domain. Under Redirections, enable Block API traffic that uses an incorrect instanced URL. If you enable this change before the related known issue is resolved, SOAP login URLs via Visualforce pages can return a 400 Bad Request error.
To review this update, from Setup, in the Quick Find box, enter Release Updates, and then select Release Updates. For Update Instanced URLs in API Traffic, follow the testing and activation steps.