* http: added a new option to upstream HTTP/2 :ref:`keepalive <envoy_v3_api_field_config.core.v3.Http2ProtocolOptions.connection_keepalive>` to send a PING ahead of a new stream if the connection has been idle for a sufficient duration.

* http: added the ability to :ref:`unescape slash sequences<envoy_v3_api_field_extensions.filters.network.http_connection_manager.v3.HttpConnectionManager.path_with_escaped_slashes_action>` in the path. Requests with unescaped slashes can be proxied, rejected or redirected to the new unescaped path. By default this feature is disabled. The default behavior can be overridden through :ref:`http_connection_manager.path_with_escaped_slashes_action<config_http_conn_man_runtime_path_with_escaped_slashes_action>` runtime variable. This action can be selectively enabled for a portion of requests by setting the :ref:`http_connection_manager.path_with_escaped_slashes_action_sampling<config_http_conn_man_runtime_path_with_escaped_slashes_action_enabled>` runtime variable.

* http: added upstream and downstream alpha HTTP/3 support! See :ref:`quic_options <envoy_v3_api_field_config.listener.v3.UdpListenerConfig.quic_options>` for downstream and the new http3_protocol_options in :ref:`http_protocol_options <envoy_v3_api_msg_extensions.upstreams.http.v3.HttpProtocolOptions>` for upstream HTTP/3.

* jwt_authn: added support to fetch remote jwks asynchronously specified by :ref:`async_fetch <envoy_v3_api_field_extensions.filters.http.jwt_authn.v3.RemoteJwks.async_fetch>`.

* listener: added ability to change an existing listener's address.

* local_rate_limit_filter: added suppoort for locally rate limiting http requests on a per connection basis. This can be enabled by setting the :ref:`local_rate_limit_per_downstream_connection <envoy_v3_api_field_extensions.filters.http.local_ratelimit.v3.LocalRateLimit.local_rate_limit_per_downstream_connection>` field to true.