nhanced External Services are generally available and enabled by default. It’s easy to use, and provides more ways to create and connect to outside services. Now, when you register a service, you get support for more complex OpenAPI 2.0 schema, nested object types, and send parameters as headers within the HTTP requests.
Where: This change applies to Lightning Experience in Enterprise, Performance, Unlimited, and Developer editions.
How: After turning on Enhanced External Services, register new external services the same way you did before. Actions generated by your schema are created as External Service Actions in Flow Builder.
Existing registrations are not automatically migrated to Enhanced External Services. For existing registrations to use the new features in Enhanced External Services, you must re-register the schema, update the flows that use the old Apex Action to the new Enhanced External Service Action and delete the old registration.