Update README with HTTP/2 details

README.rst

@@ -3,7 +3,7 @@ daphne
 
 .. image:: https://api.travis-ci.org/django/daphne.svg
     :target: https://travis-ci.org/django/daphne
-    
+
 .. image:: https://img.shields.io/pypi/v/daphne.svg
     :target: https://pypi.python.org/pypi/daphne
 
@@ -23,13 +23,11 @@ set a bind address and port (defaults to localhost, port 8000)::
 
     daphne -b 0.0.0.0 -p 8001 django_project.asgi:channel_layer
 
-
 If you intend to run daphne behind a proxy server you can use UNIX
 sockets to communicate between the two::
 
     daphne -u /tmp/daphne.sock django_project.asgi:channel_layer
 
-
 If daphne is being run inside a process manager such as
 `Circus <https://github.com/circus-tent/circus/>`_ you might
 want it to bind to a file descriptor passed down from a parent process.
@@ -37,7 +35,6 @@ To achieve this you can use the --fd flag::
 
     daphne --fd 5 django_project.asgi:channel_layer
 
-
 If you want more control over the port/socket bindings you can fall back to
 using `twisted's endpoint description strings
 <http://twistedmatrix.com/documents/current/api/twisted.internet.endpoints.html#serverFromString>`_
@@ -47,9 +44,52 @@ exist in the current directory (requires pyopenssl to be installed)::
 
     daphne -e ssl:443:privateKey=key.pem:certKey=crt.pem django_project.asgi:channel_layer
 
+Endpoints even let you use the ``txacme`` endpoint syntax to get automatic certificates
+from Let's Encrypt, which you can read more about at http://txacme.readthedocs.io/en/stable/.
 
 To see all available command line options run daphne with the *-h* flag.
 
+
+HTTP/2 Support
+--------------
+
+Daphne 1.1 and above supports terminating HTTP/2 connections natively. You'll
+need to do a couple of things to get it working, though. First, you need to
+make sure you install the Twisted ``http2`` and ``tls`` extras::
+
+    pip install -U Twisted[tls,http2]
+
+Next, because all current browsers only support HTTP/2 when using TLS, you will
+need to start Daphne with TLS turned on, which can be done using the Twisted endpoint sytax::
+
+    daphne -e ssl:443:privateKey=key.pem:certKey=crt.pem django_project.asgi:channel_layer
+
+Alternatively, you can use the ``txacme`` endpoint syntax or anything else that
+enables TLS under the hood.
+
+You will also need to be on a system that has **OpenSSL 1.0.2 or greater**; if you are
+using Ubuntu, this means you need at least 16.04.
+
+Now, when you start up Daphne, it should tell you this in the log::
+
+    2017-03-18 19:14:02,741 INFO     Starting server at ssl:port=8000:privateKey=privkey.pem:certKey=cert.pem, channel layer django_project.asgi:channel_layer.
+    2017-03-18 19:14:02,742 INFO     HTTP/2 support enabled
+
+Then, connect with a browser that supports HTTP/2, and everything should be
+working. It's often hard to tell that HTTP/2 is working, as the log Daphne gives you
+will be identical (it's HTTP, after all), and most browsers don't make it obvious
+in their network inspector windows. There are browser extensions that will let
+you know clearly if it's working or not.
+
+Daphne only supports "normal" requests over HTTP/2 at this time; there is not
+yet support for extended features like Server Push. It will, however, result in
+much faster connections and lower overheads.
+
+If you have a reverse proxy in front of your site to serve static files or
+similar, HTTP/2 will only work if that proxy understands and passes through the
+connection correctly.
+
+
 Root Path (SCRIPT_NAME)
 -----------------------