SharePoint Mobile App for iOS- Authentication type support

The support article at https://support.office.com/en-us/article/SharePoint-mobile-app-for-iOS-339402ce-16bb-4c97-9475-0c5375ccef7a contains the following statement

"For On-Premises, we do not support: ADFS, Kerberos, Basic Authentication, Digest Authentication, self signed SSL or Multiple Authentication types in one zone.

I'm confused by this statement, can anyone help me understand what they are trying to tell us?