Feature / BC break: Use PSR-7 (http-message) standard and Request-In-Response-Out-style request handler callback. Pass standard PSR-7 ServerRequestInterface and expect any standard PSR-7 ResponseInterface in return for the request handler callback. (#146 and #152 and #170 by @legionth)

// old
$app = function (Request $request, Response $response) {
    $response->writeHead(200, array('Content-Type' => 'text/plain'));
    $response->end("Hello world!\n");
};

// new
$app = function (ServerRequestInterface $request) {
    return new Response(
        200,
        array('Content-Type' => 'text/plain'),
        "Hello world!\n"
    );
};

A Content-Length header will automatically be included if the size can be determined from the response body. (#164 by @maciejmrozinski)

The request handler callback will automatically make sure that responses to HEAD requests and certain status codes, such as 204 (No Content), never contain a response body. (#156 by @clue)

The intermediary 100 Continue response will automatically be sent if demanded by a HTTP/1.1 client. (#144 by @legionth)

The request handler callback can now return a standard Promise if processing the request needs some time, such as when querying a database. Similarly, the request handler may return a streaming response if the response body comes from a ReadableStreamInterface or its size is unknown in advance.

// old
$app = function (Request $request, Response $response) use ($db) {
    $db->query()->then(function ($result) use ($response) {
        $response->writeHead(200, array('Content-Type' => 'text/plain'));
        $response->end($result);
    });
};

// new
$app = function (ServerRequestInterface $request) use ($db) {
    return $db->query()->then(function ($result) {
        return new Response(
            200,
            array('Content-Type' => 'text/plain'),
            $result
        );
    });
};

Pending promies and response streams will automatically be canceled once the client connection closes. (#187 and #188 by @clue)

The ServerRequestInterface contains the full effective request URI, server-side parameters, query parameters and parsed cookies values as defined in PSR-7. (#167 by @clue and #174, #175 and #180 by @legionth)

$app = function (ServerRequestInterface $request) {
    return new Response(
        200,
        array('Content-Type' => 'text/plain'),
        $request->getUri()->getScheme()
    );
};

Advanced: Support duplex stream response for Upgrade requests such as Upgrade: WebSocket or custom protocols and CONNECT requests (#189 and #190 by @clue)

Note that the request body will currently not be buffered and parsed by default, which depending on your particilar use-case, may limit interoperability with the PSR-7 (http-message) ecosystem. The provided streaming request body interfaces allow you to perform buffering and parsing as needed in the request handler callback. See also the README and examples for more details.

Feature / BC break: Replace request listener with callback function and use listen() method to support multiple listening sockets (#97 by @legionth and #193 by @clue)

// old
$server = new Server($socket);
$server->on('request', $app);

// new
$server = new Server($app);
$server->listen($socket);

Feature: Support the more advanced HTTP requests, such as OPTIONS * HTTP/1.1 (OPTIONS method in asterisk-form), GET http://example.com/path HTTP/1.1 (plain proxy requests in absolute-form), CONNECT example.com:443 HTTP/1.1 (CONNECT proxy requests in authority-form) and sanitize Host header value across all requests. (#157, #158, #161, #165, #169 and #173 by @clue)

Feature: Forward compatibility with Socket v1.0, v0.8, v0.7 and v0.6 and forward compatibility with Stream v1.0 and v0.7 (#154, #163, #183, #184 and #191 by @clue)

Feature: Simplify examples to ease getting started and add benchmarking example (#151 and #162 by @clue)

Improve test suite by adding tests for case insensitive chunked transfer encoding and ignoring HHVM test failures until Travis tests work again. (#150 by @legionth and #185 by @clue)