To authenticate with the SOAP API login() operation, all users must have the Use Any API Auth user permission assigned to them. Users without the Use Any API Auth user permission can no longer authenticate with SOAP API login() and will encounter an error. Beginning December 1, 2026, this requirement is enforced uniformly across all orgs and environments (production, pre-production sandboxes, etc.). You can run tests in advance using the Release Update in Setup.
Where: This change applies to Lightning Experience and Salesforce Classic in all API enabled editions.
How: Assign the Use Any API Auth user permission to users via profiles or permission sets to enable use of the SOAP API login() operation.