code>REWRITE_TCP_PROBES=false</code> environment variable in the Istiod deployment. The entire probe rewrite feature (HTTP and TCP) can also <a href=/v1.16/docs/ops/configuration/mesh/app-health-check/#liveness-and-readiness-probes-using-the-http-request-approach>be disabled</a>.</p><h2 id=default-revision-must-be-switched-when-performing-a-revision-based-upgrade>Default revision must be switched when performing a revision-based upgrade</h2><p>When installing a new Istio control plane revision the previous 