maileo supports secure email delivery features commonly used in modern email systems, including encrypted transport where the remote side also supports it. Whether a message is delivered with encryption can still depend on the capabilities of the other mail server involved.
Transport security and mailbox login security are related but separate topics. Server-to-server delivery security does not replace secure mailbox credentials and proper client configuration.
If you need stricter transport requirements, review the TLS-related settings available for your service.