diff --git a/composer.json b/composer.json
index 02c184f..b1e1d25 100644
--- a/composer.json
+++ b/composer.json
@@ -28,16 +28,16 @@
     "require": {
         "php": ">=5.3.0",
         "evenement/evenement": "^3.0 || ^2.0 || ^1.0",
-        "react/dns": "^1.11",
+        "react/dns": "^1.13",
         "react/event-loop": "^1.2",
-        "react/promise": "^3 || ^2.6 || ^1.2.1",
-        "react/stream": "^1.2"
+        "react/promise": "^3.2 || ^2.6 || ^1.2.1",
+        "react/stream": "^1.4"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.6 || ^5.7 || ^4.8.36",
-        "react/async": "^4 || ^3 || ^2",
+        "react/async": "^4.3 || ^3.3 || ^2",
         "react/promise-stream": "^1.4",
-        "react/promise-timer": "^1.10"
+        "react/promise-timer": "^1.11"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/FdServer.php b/src/FdServer.php
index b1ed777..8e46719 100644
--- a/src/FdServer.php
+++ b/src/FdServer.php
@@ -75,7 +75,7 @@ final class FdServer extends EventEmitter implements ServerInterface
      * @throws \InvalidArgumentException if the listening address is invalid
      * @throws \RuntimeException if listening on this address fails (already in use etc.)
      */
-    public function __construct($fd, LoopInterface $loop = null)
+    public function __construct($fd, $loop = null)
     {
         if (\preg_match('#^php://fd/(\d+)$#', $fd, $m)) {
             $fd = (int) $m[1];
@@ -87,6 +87,10 @@ public function __construct($fd, LoopInterface $loop = null)
             );
         }
 
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->loop = $loop ?: Loop::get();
 
         $errno = 0;
diff --git a/src/HappyEyeBallsConnector.php b/src/HappyEyeBallsConnector.php
index 98b1d58..a5511ac 100644
--- a/src/HappyEyeBallsConnector.php
+++ b/src/HappyEyeBallsConnector.php
@@ -13,15 +13,26 @@ final class HappyEyeBallsConnector implements ConnectorInterface
     private $connector;
     private $resolver;
 
-    public function __construct(LoopInterface $loop = null, ConnectorInterface $connector = null, ResolverInterface $resolver = null)
+    /**
+     * @param ?LoopInterface $loop
+     * @param ConnectorInterface $connector
+     * @param ResolverInterface $resolver
+     */
+    public function __construct($loop = null, $connector = null, $resolver = null)
     {
         // $connector and $resolver arguments are actually required, marked
         // optional for technical reasons only. Nullable $loop without default
         // requires PHP 7.1, null default is also supported in legacy PHP
         // versions, but required parameters are not allowed after arguments
         // with null default. Mark all parameters optional and check accordingly.
-        if ($connector === null || $resolver === null) {
-            throw new \InvalidArgumentException('Missing required $connector or $resolver argument');
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+        if (!$connector instanceof ConnectorInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($connector) expected React\Socket\ConnectorInterface');
+        }
+        if (!$resolver instanceof ResolverInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #3 ($resolver) expected React\Dns\Resolver\ResolverInterface');
         }
 
         $this->loop = $loop ?: Loop::get();
diff --git a/src/SecureConnector.php b/src/SecureConnector.php
index 17c229d..08255ac 100644
--- a/src/SecureConnector.php
+++ b/src/SecureConnector.php
@@ -15,8 +15,17 @@ final class SecureConnector implements ConnectorInterface
     private $streamEncryption;
     private $context;
 
-    public function __construct(ConnectorInterface $connector, LoopInterface $loop = null, array $context = array())
+    /**
+     * @param ConnectorInterface $connector
+     * @param ?LoopInterface $loop
+     * @param array $context
+     */
+    public function __construct(ConnectorInterface $connector, $loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->connector = $connector;
         $this->streamEncryption = new StreamEncryption($loop ?: Loop::get(), false);
         $this->context = $context;
diff --git a/src/SecureServer.php b/src/SecureServer.php
index d0525c9..5a202d2 100644
--- a/src/SecureServer.php
+++ b/src/SecureServer.php
@@ -122,8 +122,12 @@ final class SecureServer extends EventEmitter implements ServerInterface
      * @see TcpServer
      * @link https://www.php.net/manual/en/context.ssl.php for TLS context options
      */
-    public function __construct(ServerInterface $tcp, LoopInterface $loop = null, array $context = array())
+    public function __construct(ServerInterface $tcp, $loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         if (!\function_exists('stream_socket_enable_crypto')) {
             throw new \BadMethodCallException('Encryption not supported on your platform (HHVM < 3.8?)'); // @codeCoverageIgnore
         }
diff --git a/src/Server.php b/src/Server.php
index 7d4111e..b24c556 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -43,14 +43,18 @@ final class Server extends EventEmitter implements ServerInterface
      * For BC reasons, you can also pass the TCP socket context options as a simple
      * array without wrapping this in another array under the `tcp` key.
      *
-     * @param string|int    $uri
-     * @param LoopInterface $loop
-     * @param array         $context
+     * @param string|int     $uri
+     * @param ?LoopInterface $loop
+     * @param array          $context
      * @deprecated 1.9.0 See `SocketServer` instead
      * @see SocketServer
      */
-    public function __construct($uri, LoopInterface $loop = null, array $context = array())
+    public function __construct($uri, $loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $loop = $loop ?: Loop::get();
 
         // sanitize TCP context options if not properly wrapped
diff --git a/src/SocketServer.php b/src/SocketServer.php
index b78dc3a..e987f5f 100644
--- a/src/SocketServer.php
+++ b/src/SocketServer.php
@@ -31,8 +31,12 @@ final class SocketServer extends EventEmitter implements ServerInterface
      * @throws \InvalidArgumentException if the listening address is invalid
      * @throws \RuntimeException if listening on this address fails (already in use etc.)
      */
-    public function __construct($uri, array $context = array(), LoopInterface $loop = null)
+    public function __construct($uri, array $context = array(), $loop = null)
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #3 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         // apply default options if not explicitly given
         $context += array(
             'tcp' => array(),
diff --git a/src/TcpConnector.php b/src/TcpConnector.php
index 8cfc7bf..9d2599e 100644
--- a/src/TcpConnector.php
+++ b/src/TcpConnector.php
@@ -13,8 +13,16 @@ final class TcpConnector implements ConnectorInterface
     private $loop;
     private $context;
 
-    public function __construct(LoopInterface $loop = null, array $context = array())
+    /**
+     * @param ?LoopInterface $loop
+     * @param array $context
+     */
+    public function __construct($loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->loop = $loop ?: Loop::get();
         $this->context = $context;
     }
diff --git a/src/TcpServer.php b/src/TcpServer.php
index 235761d..01b2b46 100644
--- a/src/TcpServer.php
+++ b/src/TcpServer.php
@@ -128,8 +128,12 @@ final class TcpServer extends EventEmitter implements ServerInterface
      * @throws InvalidArgumentException if the listening address is invalid
      * @throws RuntimeException if listening on this address fails (already in use etc.)
      */
-    public function __construct($uri, LoopInterface $loop = null, array $context = array())
+    public function __construct($uri, $loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->loop = $loop ?: Loop::get();
 
         // a single port has been given => assume localhost
diff --git a/src/TimeoutConnector.php b/src/TimeoutConnector.php
index a20ea5a..9ef252f 100644
--- a/src/TimeoutConnector.php
+++ b/src/TimeoutConnector.php
@@ -12,8 +12,17 @@ final class TimeoutConnector implements ConnectorInterface
     private $timeout;
     private $loop;
 
-    public function __construct(ConnectorInterface $connector, $timeout, LoopInterface $loop = null)
+    /**
+     * @param ConnectorInterface $connector
+     * @param float $timeout
+     * @param ?LoopInterface $loop
+     */
+    public function __construct(ConnectorInterface $connector, $timeout, $loop = null)
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #3 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->connector = $connector;
         $this->timeout = $timeout;
         $this->loop = $loop ?: Loop::get();
diff --git a/src/UnixConnector.php b/src/UnixConnector.php
index 627d60f..95f932c 100644
--- a/src/UnixConnector.php
+++ b/src/UnixConnector.php
@@ -18,8 +18,15 @@ final class UnixConnector implements ConnectorInterface
 {
     private $loop;
 
-    public function __construct(LoopInterface $loop = null)
+    /**
+     * @param ?LoopInterface $loop
+     */
+    public function __construct($loop = null)
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->loop = $loop ?: Loop::get();
     }
 
diff --git a/src/UnixServer.php b/src/UnixServer.php
index cc46968..27b014d 100644
--- a/src/UnixServer.php
+++ b/src/UnixServer.php
@@ -50,8 +50,12 @@ final class UnixServer extends EventEmitter implements ServerInterface
      * @throws InvalidArgumentException if the listening address is invalid
      * @throws RuntimeException if listening on this address fails (already in use etc.)
      */
-    public function __construct($path, LoopInterface $loop = null, array $context = array())
+    public function __construct($path, $loop = null, array $context = array())
     {
+        if ($loop !== null && !$loop instanceof LoopInterface) { // manual type check to support legacy PHP < 7.1
+            throw new \InvalidArgumentException('Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        }
+
         $this->loop = $loop ?: Loop::get();
 
         if (\strpos($path, '://') === false) {
diff --git a/tests/FdServerTest.php b/tests/FdServerTest.php
index 7a97ae7..34b1fad 100644
--- a/tests/FdServerTest.php
+++ b/tests/FdServerTest.php
@@ -50,6 +50,12 @@ public function testCtorThrowsForInvalidUrl()
         new FdServer('tcp://127.0.0.1:8080', $loop);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new FdServer(0, 'loop');
+    }
+
     public function testCtorThrowsForUnknownFdWithoutCallingCustomErrorHandler()
     {
         if (!is_dir('/dev/fd') || defined('HHVM_VERSION')) {
diff --git a/tests/HappyEyeBallsConnectorTest.php b/tests/HappyEyeBallsConnectorTest.php
index 5301b3b..c4516a7 100644
--- a/tests/HappyEyeBallsConnectorTest.php
+++ b/tests/HappyEyeBallsConnectorTest.php
@@ -40,15 +40,21 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
     }
 
+    public function testConstructWithInvalidLoopThrows()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        new HappyEyeBallsConnector('loop', $this->tcp, $this->resolver);
+    }
+
     public function testConstructWithoutRequiredConnectorThrows()
     {
-        $this->setExpectedException('InvalidArgumentException');
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($connector) expected React\Socket\ConnectorInterface');
         new HappyEyeBallsConnector(null, null, $this->resolver);
     }
 
     public function testConstructWithoutRequiredResolverThrows()
     {
-        $this->setExpectedException('InvalidArgumentException');
+        $this->setExpectedException('InvalidArgumentException', 'Argument #3 ($resolver) expected React\Dns\Resolver\ResolverInterface');
         new HappyEyeBallsConnector(null, $this->tcp);
     }
 
diff --git a/tests/SecureConnectorTest.php b/tests/SecureConnectorTest.php
index e81f4a9..c115a2b 100644
--- a/tests/SecureConnectorTest.php
+++ b/tests/SecureConnectorTest.php
@@ -26,6 +26,12 @@ public function setUpConnector()
         $this->connector = new SecureConnector($this->tcp, $this->loop);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new SecureConnector($this->tcp, 'loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $connector = new SecureConnector($this->tcp);
diff --git a/tests/SecureServerTest.php b/tests/SecureServerTest.php
index a6ddcf2..6265618 100644
--- a/tests/SecureServerTest.php
+++ b/tests/SecureServerTest.php
@@ -18,6 +18,14 @@ public function setUpSkipTest()
         }
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new SecureServer($tcp, 'loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
diff --git a/tests/ServerTest.php b/tests/ServerTest.php
index f69e6cb..f3859cc 100644
--- a/tests/ServerTest.php
+++ b/tests/ServerTest.php
@@ -44,6 +44,12 @@ public function testConstructorThrowsForInvalidUri()
         $server = new Server('invalid URI', $loop);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new Server('127.0.0.1:0', 'loop');
+    }
+
     public function testConstructorCreatesExpectedTcpServer()
     {
         $server = new Server(0);
diff --git a/tests/SocketServerTest.php b/tests/SocketServerTest.php
index c7cee8e..cd53f75 100644
--- a/tests/SocketServerTest.php
+++ b/tests/SocketServerTest.php
@@ -65,6 +65,12 @@ public function testConstructorWithInvalidUriWithSchemaAndPortOnlyThrows()
         new SocketServer('tcp://0');
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #3 ($loop) expected null|React\EventLoop\LoopInterface');
+        new SocketServer('127.0.0.1:0', array(), 'loop');
+    }
+
     public function testConstructorCreatesExpectedTcpServer()
     {
         $socket = new SocketServer('127.0.0.1:0', array());
diff --git a/tests/TcpConnectorTest.php b/tests/TcpConnectorTest.php
index fb6f871..8e5f138 100644
--- a/tests/TcpConnectorTest.php
+++ b/tests/TcpConnectorTest.php
@@ -12,6 +12,12 @@ class TcpConnectorTest extends TestCase
 {
     const TIMEOUT = 5.0;
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        new TcpConnector('loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $connector = new TcpConnector();
diff --git a/tests/TcpServerTest.php b/tests/TcpServerTest.php
index 8908d1c..0c930c8 100644
--- a/tests/TcpServerTest.php
+++ b/tests/TcpServerTest.php
@@ -26,6 +26,12 @@ public function setUpServer()
         $this->port = parse_url($this->server->getAddress(), PHP_URL_PORT);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new TcpServer(0, 'loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $server = new TcpServer(0);
diff --git a/tests/TimeoutConnectorTest.php b/tests/TimeoutConnectorTest.php
index fc218c4..eab5942 100644
--- a/tests/TimeoutConnectorTest.php
+++ b/tests/TimeoutConnectorTest.php
@@ -9,6 +9,14 @@
 
 class TimeoutConnectorTest extends TestCase
 {
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $base = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+
+        $this->setExpectedException('InvalidArgumentException', 'Argument #3 ($loop) expected null|React\EventLoop\LoopInterface');
+        new TimeoutConnector($base, 0.001, 'loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $base = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
diff --git a/tests/UnixConnectorTest.php b/tests/UnixConnectorTest.php
index d7e314a..5bcd7a5 100644
--- a/tests/UnixConnectorTest.php
+++ b/tests/UnixConnectorTest.php
@@ -19,6 +19,12 @@ public function setUpConnector()
         $this->connector = new UnixConnector($this->loop);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #1 ($loop) expected null|React\EventLoop\LoopInterface');
+        new UnixConnector('loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         $connector = new UnixConnector();
diff --git a/tests/UnixServerTest.php b/tests/UnixServerTest.php
index c148de4..26f28d9 100644
--- a/tests/UnixServerTest.php
+++ b/tests/UnixServerTest.php
@@ -29,6 +29,12 @@ public function setUpServer()
         $this->server = new UnixServer($this->uds);
     }
 
+    public function testCtorThrowsForInvalidLoop()
+    {
+        $this->setExpectedException('InvalidArgumentException', 'Argument #2 ($loop) expected null|React\EventLoop\LoopInterface');
+        new UnixServer($this->getRandomSocketUri(), 'loop');
+    }
+
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
         unlink(str_replace('unix://', '', $this->uds));