diff --git a/composer.json b/composer.json
index 6b5567f21..4ab7c484e 100644
--- a/composer.json
+++ b/composer.json
@@ -47,7 +47,8 @@
     "config": {
         "allow-plugins": {
             "composer/package-versions-deprecated": true,
-            "dealerdirect/phpcodesniffer-composer-installer": true
+            "dealerdirect/phpcodesniffer-composer-installer": true,
+            "phpstan/extension-installer": true
         }
     }
 }
diff --git a/src/SAML2/Constants.php b/src/SAML2/Constants.php
index 0cc5cee71..fe12984db 100644
--- a/src/SAML2/Constants.php
+++ b/src/SAML2/Constants.php
@@ -231,6 +231,11 @@ class Constants
      */
     const NS_ECP = 'urn:oasis:names:tc:SAML:2.0:profiles:SSO:ecp';
 
+    /**
+     * The namespace for the IDP Discovery protocol.
+     */
+    const NS_IDPDISC = 'urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol';
+
     /**
      * The namespace for the SOAP protocol.
      */
diff --git a/src/SAML2/Utils.php b/src/SAML2/Utils.php
index 3d55dd0c8..450009c39 100644
--- a/src/SAML2/Utils.php
+++ b/src/SAML2/Utils.php
@@ -172,7 +172,7 @@ public static function validateSignature(array $info, XMLSecurityKey $key) : voi
 
         /** @var XMLSecurityDSig $objXMLSecDSig */
         $objXMLSecDSig = $info['Signature'];
-        
+
         /**
          * @var \DOMElement[] $sigMethod
          * @var \DOMElement $objXMLSecDSig->sigNode
@@ -221,6 +221,7 @@ public static function xpQuery(DOMNode $node, string $query) : array
             $xpCache->registerNamespace('saml_protocol', Constants::NS_SAMLP);
             $xpCache->registerNamespace('saml_assertion', Constants::NS_SAML);
             $xpCache->registerNamespace('saml_metadata', Constants::NS_MD);
+            $xpCache->registerNamespace('saml_idpdisc', Constants::NS_IDPDISC);
             $xpCache->registerNamespace('ds', XMLSecurityDSig::XMLDSIGNS);
             $xpCache->registerNamespace('xenc', XMLSecEnc::XMLENCNS);
         }
diff --git a/src/SAML2/XML/idpdisc/DiscoveryResponse.php b/src/SAML2/XML/idpdisc/DiscoveryResponse.php
new file mode 100644
index 000000000..9ac0a2019
--- /dev/null
+++ b/src/SAML2/XML/idpdisc/DiscoveryResponse.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SAML2\XML\idpdisc;
+
+use DOMElement;
+
+use SAML2\Constants;
+use SAML2\XML\md\IndexedEndpointType;
+use Webmozart\Assert\Assert;
+
+/**
+ * Class representing SAML 2 idpdisc:DiscoveryResponse.
+ *
+ * @package SimpleSAMLphp
+ */
+class DiscoveryResponse extends IndexedEndpointType
+{
+    /**
+     * Initialize an IndexedEndpointType.
+     *
+     * @param \DOMElement|null $xml The XML element we should load.
+     * @throws \Exception
+     */
+    public function __construct(?DOMElement $xml = null)
+    {
+        parent::__construct($xml);
+    }
+
+
+    /**
+     * Set the value of the Binding property.
+     *
+     * @param string $binding
+     * @return void
+     */
+    public function setBinding(string $binding) : void
+    {
+        Assert::same($binding, Constants::NS_IDPDISC);
+
+        parent::setBinding($binding);
+    }
+
+
+    /**
+     * Add this endpoint to an XML element.
+     *
+     * @param \DOMElement $parent The element we should append this endpoint to.
+     * @param string $name The name of the element we should create.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent, string $name) : DOMElement
+    {
+        return $this->toXMLInternal($parent, Constants::NS_IDPDISC, 'idpdisc:DiscoveryResponse');
+    }
+}
diff --git a/src/SAML2/XML/md/EndpointType.php b/src/SAML2/XML/md/EndpointType.php
index ab4e986d2..3747355cd 100644
--- a/src/SAML2/XML/md/EndpointType.php
+++ b/src/SAML2/XML/md/EndpointType.php
@@ -59,7 +59,7 @@ public function __construct(?DOMElement $xml = null)
         if (!$xml->hasAttribute('Binding')) {
             throw new \Exception('Missing Binding on '.$xml->tagName);
         }
-        $this->Binding = $xml->getAttribute('Binding');
+        $this->setBinding($xml->getAttribute('Binding'));
 
         if (!$xml->hasAttribute('Location')) {
             throw new \Exception('Missing Location on '.$xml->tagName);
@@ -230,11 +230,12 @@ public function setResponseLocation(?string $responseLocation = null) : void
      *
      * @param \DOMElement $parent The element we should append this endpoint to.
      * @param string $name The name of the element we should create.
+     * @param string $namespace The namespace of the element we should create
      * @return \DOMElement
      */
-    public function toXML(DOMElement $parent, string $name) : DOMElement
+    protected function toXMLInternal(DOMElement $parent, string $namespace, string $name) : DOMElement
     {
-        $e = $parent->ownerDocument->createElementNS(Constants::NS_MD, $name);
+        $e = $parent->ownerDocument->createElementNS($namespace, $name);
         $parent->appendChild($e);
 
         if (empty($this->Binding)) {
@@ -257,4 +258,17 @@ public function toXML(DOMElement $parent, string $name) : DOMElement
 
         return $e;
     }
+
+
+    /**
+     * Convert this Attribute to XML.
+     *
+     * @param \DOMElement $parent The element we should append this Attribute to.
+     * @param string $name
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent, string $name) : \DOMElement
+    {
+        return $this->toXMLInternal($parent, Constants::NS_MD, $name);
+    }
 }
diff --git a/src/SAML2/XML/md/Extensions.php b/src/SAML2/XML/md/Extensions.php
index fda7a4a3c..14a9f6a9f 100644
--- a/src/SAML2/XML/md/Extensions.php
+++ b/src/SAML2/XML/md/Extensions.php
@@ -12,6 +12,7 @@
 use SAML2\XML\alg\DigestMethod;
 use SAML2\XML\alg\SigningMethod;
 use SAML2\XML\Chunk;
+use SAML2\XML\idpdisc\DiscoveryResponse;
 use SAML2\XML\mdattr\EntityAttributes;
 use SAML2\XML\mdrpi\Common as MDRPI;
 use SAML2\XML\mdrpi\PublicationInfo;
@@ -32,6 +33,7 @@ class Extensions
      *
      * @param \DOMElement $parent The element that may contain the md:Extensions element.
      * @return (\SAML2\XML\shibmd\Scope|
+     *          \SAML2\XML\idpdisc\DiscoveryResponse|
      *          \SAML2\XML\mdattr\EntityAttributes|
      *          \SAML2\XML\mdrpi\RegistrationInfo|
      *          \SAML2\XML\mdrpi\PublicationInfo|
@@ -45,6 +47,9 @@ public static function getList(DOMElement $parent) : array
     {
         $ret = [];
         $supported = [
+            Constants::NS_IDPDISC => [
+                'DiscoveryResponse' => DiscoveryResponse::class,
+            ],
             Scope::NS => [
                 'Scope' => Scope::class,
             ],
diff --git a/src/SAML2/XML/md/IndexedEndpointType.php b/src/SAML2/XML/md/IndexedEndpointType.php
index 162c137a2..341994ca6 100644
--- a/src/SAML2/XML/md/IndexedEndpointType.php
+++ b/src/SAML2/XML/md/IndexedEndpointType.php
@@ -104,11 +104,12 @@ public function setIsDefault(?bool $flag = null) : void
      *
      * @param \DOMElement $parent The element we should append this endpoint to.
      * @param string $name The name of the element we should create.
+     * @param string $namespace The namesapce of the element we should create.
      * @return \DOMElement
      */
-    public function toXML(DOMElement $parent, string $name) : DOMElement
+    protected function toXMLInternal(DOMElement $parent, string $namespace, string $name) : DOMElement
     {
-        $e = parent::toXML($parent, $name);
+        $e = parent::toXMLInternal($parent, $namespace, $name);
         $e->setAttribute('index', strval($this->index));
 
         if (is_bool($this->isDefault)) {
diff --git a/tests/SAML2/XML/md/EndpointTypeTest.php b/tests/SAML2/XML/md/EndpointTypeTest.php
index 0763e660d..fb49abafe 100644
--- a/tests/SAML2/XML/md/EndpointTypeTest.php
+++ b/tests/SAML2/XML/md/EndpointTypeTest.php
@@ -25,8 +25,8 @@ public function testMarshalling() : void
 
         $document = DOMDocumentFactory::fromString('<root />');
         $endpointTypeElement = $endpointType->toXML($document->firstChild, 'md:Test');
-
         $endpointTypeElements = Utils::xpQuery($endpointTypeElement, '/root/saml_metadata:Test');
+
         $this->assertCount(1, $endpointTypeElements);
         $endpointTypeElement = $endpointTypeElements[0];
 
diff --git a/tests/SAML2/XML/md/IndexedEndpointTypeTest.php b/tests/SAML2/XML/md/IndexedEndpointTypeTest.php
index 4698dda14..d349b2bee 100644
--- a/tests/SAML2/XML/md/IndexedEndpointTypeTest.php
+++ b/tests/SAML2/XML/md/IndexedEndpointTypeTest.php
@@ -4,7 +4,10 @@
 
 namespace SAML2\XML\md;
 
+use InvalidArgumentException;
+use SAML2\Constants;
 use SAML2\DOMDocumentFactory;
+use SAML2\XML\idpdisc\DiscoveryResponse;
 use SAML2\XML\md\IndexedEndpointType;
 use SAML2\Utils;
 
@@ -16,7 +19,7 @@ class IndexedEndpointTypeTest extends \PHPUnit\Framework\TestCase
     /**
      * @return void
      */
-    public function testMarshalling() : void
+    public function testMarshalling(): void
     {
         $indexedEndpointType = new IndexedEndpointType();
         $indexedEndpointType->setBinding('TestBinding');
@@ -50,4 +53,41 @@ public function testMarshalling() : void
         $this->assertCount(1, $indexedEndpointTypeElement);
         $this->assertTrue(!$indexedEndpointTypeElement[0]->hasAttribute('isDefault'));
     }
+
+
+    /**
+     * @return void
+     */
+    public function testMarshallingDiscoveryResponse(): void
+    {
+        $discoResponse = new DiscoveryResponse();
+        $discoResponse->setBinding(Constants::NS_IDPDISC);
+        $discoResponse->setLocation('TestLocation');
+        $discoResponse->setIndex(42);
+        $discoResponse->setIsDefault(false);
+
+        $document = DOMDocumentFactory::fromString('<root />');
+        $discoResponseElement = $discoResponse->toXML($document->firstChild, 'idpdisc:DiscoverResponse');
+
+        $discoResponseElements = Utils::xpQuery($discoResponseElement, '/root/saml_idpdisc:DiscoveryResponse');
+        $this->assertCount(1, $discoResponseElements);
+        $discoResponseElement = $discoResponseElements[0];
+
+        $this->assertEquals(Constants::NS_IDPDISC, $discoResponseElement->getAttribute('Binding'));
+        $this->assertEquals('TestLocation', $discoResponseElement->getAttribute('Location'));
+        $this->assertEquals('42', $discoResponseElement->getAttribute('index'));
+        $this->assertEquals('false', $discoResponseElement->getAttribute('isDefault'));
+    }
+
+
+    /**
+     * @return void
+     */
+    public function testMarshallingDiscoveryResponseWrongBindingFails(): void
+    {
+        $discoResponse = new DiscoveryResponse();
+
+        $this->expectException(InvalidArgumentException::class);
+        $discoResponse->setBinding('This is not OK.');
+    }
 }