At the same time Apple encourages the use of HTTPS with App Transport Security (ATS).
Starting in iOS 9.0 and OS X v10.11, a new security feature
called App Transport Security (ATS) is available to apps and is
enabled by default. It improves the privacy and data integrity
of connections between an app and web services by enforcing
additional security requirements for HTTP-based networking
requests. Specifically, with ATS enabled, HTTP connections must
use HTTPS (RFC 2818). Attempts to connect using insecure HTTP
fail. Furthermore, HTTPS requests must use best practices for
secure communications.
Does that mean that in the future nearly every App will need the ERN?