 two key updates to help control the TCP metadata exchange:</p><ul><li><strong>Fallback Metadata Discovery</strong> Istio can now use a backup method to collect metadata. To use this, turn on
the <code>PEER_METADATA_DISCOVERY</code> in the proxy and <code>PILOT_ENABLE_AMBIENT_CONTROLLERS</code> in the control plane.</li><li><strong>ALPN Token Control</strong>: There&rsquo;s a new setting called <code>PILOT_DISABLE_MX_ALPN</code> for the control plane. This lets you stop
using a specific token <code>istio-pe