diff --git a/.State b/.State
deleted file mode 100644
index a604de4..0000000
--- a/.State
+++ /dev/null
@@ -1 +0,0 @@
-finalized
diff --git a/Connection.php b/Source/Connection.php
similarity index 89%
rename from Connection.php
rename to Source/Connection.php
index 1f2dd59..4077941 100644
--- a/Connection.php
+++ b/Source/Connection.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -43,9 +45,6 @@
  * Specification can be found here:
  * http://fastcgi.com/devkit/doc/fcgi-spec.html.
  * Inspired by PHP SAPI code: php://sapi/cgi/fastcgi.*.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 abstract class Connection
 {
@@ -102,13 +101,8 @@ abstract class Connection
 
     /**
      * Pack data to a packet.
-     *
-     * @param   int     $type       Packet's type.
-     * @param   string  $content    Content.
-     * @param   id      $id         Packet's ID.
-     * @return  string
      */
-    public function pack($type, $content, $id = 1)
+    public function pack(int $type, string $content, int $id = 1): string
     {
         $length = strlen($content);
 
@@ -126,11 +120,8 @@ public function pack($type, $content, $id = 1)
 
     /**
      * Pack pairs (key/value).
-     *
-     * @param   array  $pairs    Keys/values array.
-     * @return  string
      */
-    public function packPairs(array $pairs)
+    public function packPairs(array $pairs): ?string
     {
         $out = null;
 
@@ -160,11 +151,8 @@ public function packPairs(array $pairs)
 
     /**
      * Unpack pairs (key/value).
-     *
-     * @param   string  $pack    Packet to unpack.
-     * @return  string
      */
-    public function unpackPairs($pack)
+    public function unpackPairs(string $pack): array
     {
         if (null === $length) {
             $length = strlen($pack);
@@ -203,8 +191,6 @@ public function unpackPairs($pack)
 
     /**
      * Read a packet.
-     *
-     * @return  array
      */
     protected function readPack()
     {
@@ -243,9 +229,6 @@ protected function readPack()
 
     /**
      * Read data.
-     *
-     * @param   int     $length    Length of data to read.
-     * @return  string
      */
-    abstract protected function read($length);
+    abstract protected function read(int $length): string;
 }
diff --git a/Exception/CannotMultiplex.php b/Source/Exception/CannotMultiplex.php
similarity index 93%
rename from Exception/CannotMultiplex.php
rename to Source/Exception/CannotMultiplex.php
index 554959b..7378ddc 100644
--- a/Exception/CannotMultiplex.php
+++ b/Source/Exception/CannotMultiplex.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -39,13 +41,10 @@
 /**
  * Class \Hoa\Fastcgi\Exception\CannotMultiplex.
  *
- * Extending the \Hoa\Fastcgi\Exception class.
+ * Extending the `Hoa\Fastcgi\Exception` class.
  * This happens when a Web server sends concurrent requests over one connection
  * to an application that is designed to process one request at a time per
  * connection.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 class CannotMultiplex extends Exception
 {
diff --git a/Exception/Exception.php b/Source/Exception/Exception.php
similarity index 90%
rename from Exception/Exception.php
rename to Source/Exception/Exception.php
index a09a4bc..b920521 100644
--- a/Exception/Exception.php
+++ b/Source/Exception/Exception.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -42,10 +44,7 @@
 /**
  * Class \Hoa\Fastcgi\Exception.
  *
- * Extending the \Hoa\Exception\Exception class.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
+ * Extending the `Hoa\Exception\Exception` class.
  */
 class Exception extends HoaException
 {
@@ -54,4 +53,4 @@ class Exception extends HoaException
 /**
  * Flex entity.
  */
-Consistency::flexEntity('Hoa\Fastcgi\Exception\Exception');
+Consistency::flexEntity(Exception::class);
diff --git a/Exception/Overloaded.php b/Source/Exception/Overloaded.php
similarity index 93%
rename from Exception/Overloaded.php
rename to Source/Exception/Overloaded.php
index 0ee20c9..65dad0e 100644
--- a/Exception/Overloaded.php
+++ b/Source/Exception/Overloaded.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -39,12 +41,9 @@
 /**
  * Class \Hoa\Fastcgi\Exception\Overloaded.
  *
- * Extending the \Hoa\Fastcgi\Exception class.
+ * Extending the `Hoa\Fastcgi\Exception` class.
  * This happens when the application runs out of some resource, e.g. database
  * connections.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 class Overloaded extends Exception
 {
diff --git a/Exception/UnknownRole.php b/Source/Exception/UnknownRole.php
similarity index 93%
rename from Exception/UnknownRole.php
rename to Source/Exception/UnknownRole.php
index 0821ffd..27b591a 100644
--- a/Exception/UnknownRole.php
+++ b/Source/Exception/UnknownRole.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -39,12 +41,9 @@
 /**
  * Class \Hoa\Fastcgi\Exception\UnknownRole.
  *
- * Extending the \Hoa\Fastcgi\Exception class.
+ * Extending the `Hoa\Fastcgi\Exception` class.
  * This happens when the Web server has specified a role that is unknown to the
  * application.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 class UnknownRole extends Exception
 {
diff --git a/Exception/UnknownStatus.php b/Source/Exception/UnknownStatus.php
similarity index 93%
rename from Exception/UnknownStatus.php
rename to Source/Exception/UnknownStatus.php
index da4d949..6ff17f9 100644
--- a/Exception/UnknownStatus.php
+++ b/Source/Exception/UnknownStatus.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -39,11 +41,8 @@
 /**
  * Class \Hoa\Fastcgi\Exception\UnknownStatus.
  *
- * Extending the \Hoa\Fastcgi\Exception class.
+ * Extending the `Hoa\Fastcgi\Exception` class.
  * This happens when the response has an unknown status.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 class UnknownStatus extends Exception
 {
diff --git a/Responder.php b/Source/Responder.php
similarity index 87%
rename from Responder.php
rename to Source/Responder.php
index 2b927d1..d939147 100644
--- a/Responder.php
+++ b/Source/Responder.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * Hoa
  *
@@ -43,9 +45,6 @@
  *
  * A FastCGI client with a responder role.
  * Inspired by PHP SAPI code: php://sapi/cgi/fastcgi.*.
- *
- * @copyright  Copyright © 2007-2017 Hoa community
- * @license    New BSD License
  */
 class Responder extends Connection
 {
@@ -133,21 +132,21 @@ class Responder extends Connection
     /**
      * Client socket connection.
      *
-     * @var \Hoa\Socket\Client
+     * @var ?Socket\Client
      */
     protected $_client          = null;
 
     /**
      * Response's output.
      *
-     * @var string
+     * @var ?string
      */
     protected $_responseOutput  = null;
 
     /**
      * Response's error.
      *
-     * @var string
+     * @var ?string
      */
     protected $_responseError   = null;
 
@@ -162,8 +161,6 @@ class Responder extends Connection
 
     /**
      * Constructor.
-     *
-     * @param   \Hoa\Socket\Client  $client    Client connection.
      */
     public function __construct(Socket\Client $client)
     {
@@ -174,18 +171,8 @@ public function __construct(Socket\Client $client)
 
     /**
      * Send data on a FastCGI.
-     *
-     * @param   array   $headers    Headers.
-     * @param   string  $content    Content (e.g. key=value for POST).
-     * @return  string
-     * @throws  \Hoa\Socket\Exception
-     * @throws  \Hoa\Fastcgi\Exception
-     * @throws  \Hoa\Fastcgi\Exception\CannotMultiplex
-     * @throws  \Hoa\Fastcgi\Exception\Overloaded
-     * @throws  \Hoa\Fastcgi\Exception\UnknownRole
-     * @throws  \Hoa\Fastcgi\Exception\UnknownStatus
      */
-    public function send(array $headers, $content = null)
+    public function send(array $headers, ?string $content = null): string
     {
         $this->_responseOutput  = null;
         $this->_responseError   = null;
@@ -304,52 +291,40 @@ public function send(array $headers, $content = null)
 
     /**
      * Get response content.
-     *
-     * @return  ?string
      */
-    public function getResponseContent()
+    public function getResponseContent(): ?string
     {
         return $this->_responseOutput;
     }
 
     /**
      * Get response error if any.
-     *
-     * @return  ?string
      */
-    public function getResponseError()
+    public function getResponseError(): ?string
     {
         return $this->_responseError;
     }
 
     /**
      * Get response headers.
-     *
-     * @return  array
      */
-    public function getResponseHeaders()
+    public function getResponseHeaders(): array
     {
         return $this->_responseHeaders;
     }
 
     /**
      * Read data.
-     *
-     * @param   int     $length    Length of data to read.
-     * @return  string
      */
-    protected function read($length)
+    protected function read(int $length): ?string
     {
         return $this->getClient()->read($length);
     }
 
     /**
      * Set client.
-     *
-     * @param   \Hoa\Socket\Client  $client    Client.
-     * @return  \Hoa\Socket\Client
      */
-    public function setClient(Socket\Client $client)
+    public function setClient(Socket\Client $client): ?Socket\Client
     {
         $old           = $this->_client;
         $this->_client = $client;
@@ -359,10 +334,8 @@ public function setClient(Socket\Client $client)
 
     /**
      * Get client.
-     *
-     * @return  \Hoa\Socket\Client
      */
-    public function getClient()
+    public function getClient(): Socket\Client
     {
         return $this->_client;
     }
diff --git a/composer.json b/composer.json
index 0112ba1..5c842fe 100644
--- a/composer.json
+++ b/composer.json
@@ -23,16 +23,17 @@
         "source": "https://central.hoa-project.net/Resource/Library/Fastcgi"
     },
     "require": {
-        "hoa/consistency": "~1.0",
-        "hoa/exception"  : "~1.0",
-        "hoa/socket"     : "~1.0"
+        "php"            : ">=7.1",
+        "hoa/consistency": "dev-master",
+        "hoa/exception"  : "dev-master",
+        "hoa/socket"     : "dev-master"
     },
     "require-dev": {
-        "hoa/test": "~2.0"
+        "hoa/test": "dev-master"
     },
     "autoload": {
         "psr-4": {
-            "Hoa\\Fastcgi\\": "."
+            "Hoa\\Fastcgi\\": "Source"
         }
     },
     "extra": {