diff --git a/README.rst b/README.rst
index 86ca5a6a..d7bc328c 100644
--- a/README.rst
+++ b/README.rst
@@ -841,7 +841,7 @@ information.  Here is sample output from ``nghttpd``:
 nghttpx - proxy
 +++++++++++++++
 
-``nghttpx`` is a multi-threaded reverse proxy for HTTP/2, and
+``nghttpx`` is a multi-threaded reverse proxy for HTTP/3, HTTP/2, and
 HTTP/1.1, and powers http://nghttp2.org and supports HTTP/2 server
 push.
 
@@ -862,16 +862,16 @@ ticket keys among multiple ``nghttpx`` instances via memcached.
 
 ``nghttpx`` has 2 operation modes:
 
-================== ================ ================ =============
-Mode option        Frontend         Backend          Note
-================== ================ ================ =============
-default mode       HTTP/2, HTTP/1.1 HTTP/1.1, HTTP/2 Reverse proxy
-``--http2-proxy``  HTTP/2, HTTP/1.1 HTTP/1.1, HTTP/2 Forward proxy
-================== ================ ================ =============
+================== ======================== ================ =============
+Mode option        Frontend                 Backend          Note
+================== ======================== ================ =============
+default mode       HTTP/3, HTTP/2, HTTP/1.1 HTTP/1.1, HTTP/2 Reverse proxy
+``--http2-proxy``  HTTP/3, HTTP/2, HTTP/1.1 HTTP/1.1, HTTP/2 Forward proxy
+================== ======================== ================ =============
 
 The interesting mode at the moment is the default mode.  It works like
-a reverse proxy and listens for HTTP/2, and HTTP/1.1 and can be
-deployed as a SSL/TLS terminator for existing web server.
+a reverse proxy and listens for HTTP/3, HTTP/2, and HTTP/1.1 and can
+be deployed as a SSL/TLS terminator for existing web server.
 
 In all modes, the frontend connections are encrypted by SSL/TLS by
 default.  To disable encryption, use the ``no-tls`` keyword in
@@ -889,16 +889,16 @@ server:
 
 .. code-block:: text
 
-    Client <-- (HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/1.1, HTTP/2) --> Web Server
-                                    [reverse proxy]
+    Client <-- (HTTP/3, HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/1.1, HTTP/2) --> Web Server
+                                            [reverse proxy]
 
 With the ``--http2-proxy`` option, it works as forward proxy, and it
 is so called secure HTTP/2 proxy:
 
 .. code-block:: text
 
-    Client <-- (HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/1.1) --> Proxy
-                                     [secure proxy]          (e.g., Squid, ATS)
+    Client <-- (HTTP/3, HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/1.1) --> Proxy
+                                             [secure proxy]          (e.g., Squid, ATS)
 
 The ``Client`` in the above example needs to be configured to use
 ``nghttpx`` as secure proxy.
@@ -930,7 +930,7 @@ proxy through an HTTP proxy:
 
 .. code-block:: text
 
-    Client <-- (HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/2) --
+    Client <-- (HTTP/3, HTTP/2, HTTP/1.1) --> nghttpx <-- (HTTP/2) --
 
             --===================---> HTTP/2 Proxy
               (HTTP proxy tunnel)     (e.g., nghttpx -s)
@@ -938,8 +938,8 @@ proxy through an HTTP proxy:
 Benchmarking tool
 -----------------
 
-The ``h2load`` program is a benchmarking tool for HTTP/2.  The UI of
-``h2load`` is heavily inspired by ``weighttp``
+The ``h2load`` program is a benchmarking tool for HTTP/3, HTTP/2, and
+HTTP/1.1.  The UI of ``h2load`` is heavily inspired by ``weighttp``
 (https://github.com/lighttpd/weighttp).  The typical usage is as
 follows:
 
diff --git a/doc/sources/nghttpx-howto.rst b/doc/sources/nghttpx-howto.rst
index 27b4cc94..a0f2153b 100644
--- a/doc/sources/nghttpx-howto.rst
+++ b/doc/sources/nghttpx-howto.rst
@@ -14,8 +14,8 @@ Default mode
 
 If nghttpx is invoked without :option:`--http2-proxy`, it operates in
 default mode.  In this mode, it works as reverse proxy (gateway) for
-both HTTP/2 and HTTP/1 clients to backend servers.  This is also known
-as "HTTP/2 router".
+both HTTP/3, HTTP/2 and HTTP/1 clients to backend servers.  This is
+also known as "HTTP/2 router".
 
 By default, frontend connection is encrypted using SSL/TLS.  So
 server's private key and certificate must be supplied to the command
@@ -28,6 +28,9 @@ the frontend, and an HTTP/1 connection can be upgraded to HTTP/2 using
 HTTP Upgrade.  Starting HTTP/2 connection by sending HTTP/2 connection
 preface is also supported.
 
+In order to receive HTTP/3 traffic, use ``quic`` parameter in
+:option:`--frontend` option (.e.g, ``--frontend='*,443;quic'``)
+
 nghttpx can listen on multiple frontend addresses.  This is achieved
 by using multiple :option:`--frontend` options.  For each frontend
 address, TLS can be enabled or disabled.
@@ -509,6 +512,8 @@ Bootstrapping WebSockets with HTTP/2 for both frontend and backend
 connections.  This feature is enabled by default and no configuration
 is required.
 
+WebSockets over HTTP/3 is also supported.
+
 HTTP/3
 ------
 
diff --git a/src/shrpx.cc b/src/shrpx.cc
index 1aa47dc4..5189ee7b 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -1965,7 +1965,7 @@ void print_version(std::ostream &out) {
 namespace {
 void print_usage(std::ostream &out) {
   out << R"(Usage: nghttpx [OPTIONS]... [<PRIVATE_KEY> <CERT>]
-A reverse proxy for HTTP/2, and HTTP/1.)"
+A reverse proxy for HTTP/3, HTTP/2, and HTTP/1.)"
       << std::endl;
 }
 } // namespace