The Destination controller's Get API accepts queries for both fully qualified authorities as well as for IP addresses. However, as of stable-2.9.0, the Linkerd proxy will never send IP address queries to the Get API. In order to maintain one version of backwards compatibility between the proxy and the control plane, the destination control should continue to support IP address Get queries in stable-2.10. However, we should drop support for IP address queries to Destination.Get in stable-2.11 which will allow us to simplify the IP watching logic.

In contrast, the GetProfiles API must continue to support fully qualified authority queries (used by the inbound proxy) and IP address queries (used by the outbound proxy).