Socket.IO 2.0.0
====================

Socket.IO 2.0.0 is finally here! This major release brings several
performance improvements:

-  `uws <https://github.com/uWebSockets/uWebSockets>`_ is now the
   default Websocket engine. It should bring significant improvement in
   performance (particularly in terms of memory consumption) (`release
   note of
   Engine.IO <https://github.com/socketio/engine.io/releases/tag/2.0.0>`_)

-  the Engine.IO and Socket.IO handshake packets were merged, reducing
   the number of roundtrips necessary to establish a connection.
   (`#2833 <https://github.com/socketio/socket.io/pull/2833>`_)

-  it is now possible to provide a custom parser according to the needs
   of your application
   (`#2829 <https://github.com/socketio/socket.io/pull/2829>`_). Please
   take a look at the
   `example <https://github.com/socketio/socket.io/tree/master/examples/custom-parsers>`_
   for more information.

Please note that this release is not backward-compatible, due to:

-  a breaking change related to utf-8 encoding in
   `engine.io-parser <https://github.com/socketio/engine.io-parser/pull/81>`_

-  an update to make the socket id on the client match the id on the
   server-side
   (`#1058 <https://github.com/socketio/socket.io-client/pull/1058>`_)

Related packages were updated accordingly:

-  socket.io-redis version
   `5.x <https://github.com/socketio/socket.io-redis/releases/tag/5.0.0>`_

-  socket.io-emitter version
   `3.x <https://github.com/socketio/socket.io-emitter/releases/tag/3.0.0>`_

Get the latest client from the CDN:

.. code:: html

   <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.1/socket.io.js"></script>