As of #417, Envoy Mobile defaults traffic to HTTP/2. Depending on the server being communicated with, however, this can potentially cause problems with ALPN if the upstream server doesn't support HTTP/2. To resolve this, Envoy Mobile should be capable of doing this negotiation between HTTP/1.1 and HTTP/2.

There's an upstream issue in Envoy tracking adding support for this: envoyproxy/envoy#3431.

Once support is added, the demo apps / liveliness CI tests should be updated to test both HTTP/1.1 and HTTP/2.