The Salesforce Connect cross-org adapter now supports named credentials for authentication. The SOAP login() call is being retired, and password authentication, and OAuth 2.0 authentication won't be supported in the future, so we recommend that you migrate any cross-org adapter external data sources to use named credentials, a more robust and secure authentication method.
Where: This change applies to Lightning Experience and Salesforce Classic (not available in all orgs) in Enterprise, Performance, Unlimited, and Developer editions.
How: In the provider org, first create an external client app and get the consumer key and secret. In the subscriber org, create the external credential or external auth identity provider and use the consumer key and secret. Add a named credential that uses the auth provider you created. Then, when you create a cross-org adapter external data source, there’s a new Authentication Method field. For an existing external data source that uses login(), the field value is Legacy. When you create a new external data source or migrate an existing one, select Named Credential. In the Named Credential field, select the named credential to use for authentication.