diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 417cc7e..ea99efc 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -19,9 +19,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-version: ['8.5']
+        php-version: ['8.5', '8.6']
 
-    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_phplinter.yml@v1
+    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_phplinter.yml@release-2.x
     secrets: inherit
     with:
       php-version: ${{ matrix.php-version }}
@@ -31,7 +31,7 @@ jobs:
     strategy:
       fail-fast: false
 
-    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_linter.yml@v1
+    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_linter.yml@release-2.x
     secrets: inherit
     with:
       enable_eslinter: false
@@ -47,7 +47,7 @@ jobs:
       fail-fast: false
       matrix:
         operating-system: [ubuntu-latest]
-        php-versions: ['8.5']
+        php-versions: ['8.5', '8.6']
 
     steps:
       - name: Setup PHP, with composer and extensions
@@ -57,7 +57,7 @@ jobs:
           php-version: ${{ matrix.php-versions }}
           extensions: ctype, date, dom, filter, hash, intl, mbstring, openssl, pcre, soap, sodium, spl, xml
           tools: composer
-          ini-values: error_reporting=E_ALL
+          ini-values: error_reporting=E_ALL, display_errors=on
           coverage: pcov
 
       - name: Setup problem matchers for PHP
@@ -71,7 +71,7 @@ jobs:
           git config --global core.autocrlf false
           git config --global core.eol lf
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -109,7 +109,7 @@ jobs:
       fail-fast: true
       matrix:
         operating-system: [windows-latest]
-        php-versions: ['8.5']
+        php-versions: ['8.5', '8.6']
 
     steps:
       - name: Setup PHP, with composer and extensions
@@ -119,7 +119,7 @@ jobs:
           php-version: ${{ matrix.php-versions }}
           extensions: ctype, date, dom, filter, hash, intl, mbstring, openssl, pcre, soap, sodium, spl, xml, zip
           tools: composer
-          ini-values: error_reporting=E_ALL
+          ini-values: error_reporting=E_ALL, display_errors=on
           coverage: none
 
       - name: Setup problem matchers for PHP
@@ -133,7 +133,7 @@ jobs:
           git config --global core.autocrlf false
           git config --global core.eol lf
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$env:GITHUB_ENV"
@@ -171,7 +171,7 @@ jobs:
       - name: Setup problem matchers for PHP
         run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -225,7 +225,7 @@ jobs:
       - name: Setup problem matchers for PHP
         run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -254,7 +254,7 @@ jobs:
     runs-on: [ubuntu-latest]
     needs: [unit-tests-linux]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
 
       - uses: actions/download-artifact@v8
         with:
diff --git a/composer.json b/composer.json
index d48454b..e051ab6 100644
--- a/composer.json
+++ b/composer.json
@@ -18,12 +18,12 @@
         "psr/clock": "~1.0",
         "psr/log": "~3.0",
         "simplesamlphp/assert": "~2.0",
-        "simplesamlphp/xml-common": "~2.8",
-        "simplesamlphp/xml-security": "~2.3"
+        "simplesamlphp/xml-common": "dev-feature/dom-migration-php84",
+        "simplesamlphp/xml-security": "dev-feature/dom-migration-php84"
     },
     "require-dev": {
         "beste/clock": "~3.0",
-        "simplesamlphp/simplesamlphp-test-framework": "~1.11"
+        "simplesamlphp/simplesamlphp-test-framework": "~2.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/SAML11/Utils/XPath.php b/src/SAML11/Utils/XPath.php
index cb1e61e..b74ed7a 100644
--- a/src/SAML11/Utils/XPath.php
+++ b/src/SAML11/Utils/XPath.php
@@ -4,8 +4,7 @@
 
 namespace SimpleSAML\SAML11\Utils;
 
-use DOMNode;
-use DOMXPath;
+use Dom;
 use SimpleSAML\SAML11\Constants as C;
 
 /**
@@ -16,15 +15,15 @@
 class XPath extends \SimpleSAML\XMLSecurity\Utils\XPath
 {
     /**
-     * Get a DOMXPath object that can be used to search for SAML elements.
+     * Get a Dom\XPath object that can be used to search for SAML elements.
      *
-     * @param \DOMNode $node The document to associate to the DOMXPath object.
+     * @param \Dom\Node $node The document to associate to the Dom\XPath object.
      * @param bool $autoregister Whether to auto-register all namespaces used in the document
      *
-     * @return \DOMXPath A DOMXPath object ready to use in the given document, with several
+     * @return \Dom\XPath A Dom\XPath object ready to use in the given document, with several
      *   saml-related namespaces already registered.
      */
-    public static function getXPath(DOMNode $node, bool $autoregister = false): DOMXPath
+    public static function getXPath(Dom\Node $node, bool $autoregister = false): Dom\XPath
     {
         $xp = parent::getXPath($node, $autoregister);
 
diff --git a/src/SAML11/XML/CanonicalizableElementTrait.php b/src/SAML11/XML/CanonicalizableElementTrait.php
index 88b53e7..7e440f2 100644
--- a/src/SAML11/XML/CanonicalizableElementTrait.php
+++ b/src/SAML11/XML/CanonicalizableElementTrait.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\XMLSecurity\Constants as C;
 use SimpleSAML\XMLSecurity\Exception\CanonicalizationFailedException;
@@ -26,7 +26,7 @@ trait CanonicalizableElementTrait
      * Process all transforms specified by a given Reference element.
      *
      * @param \SimpleSAML\XMLSecurity\XML\ds\Transforms $transforms The transforms to apply.
-     * @param \DOMElement $data The data referenced.
+     * @param \Dom\Element $data The data referenced.
      *
      * @return string The canonicalized data after applying all transforms specified by $ref.
      *
@@ -34,7 +34,7 @@ trait CanonicalizableElementTrait
      */
     public function processTransforms(
         Transforms $transforms,
-        DOMElement $data,
+        Dom\Element $data,
     ): string {
         Assert::maxCount(
             $transforms->getTransform(),
diff --git a/src/SAML11/XML/SignableElementTrait.php b/src/SAML11/XML/SignableElementTrait.php
index c3b59ae..4aaa9b2 100644
--- a/src/SAML11/XML/SignableElementTrait.php
+++ b/src/SAML11/XML/SignableElementTrait.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Compat\ContainerSingleton;
 use SimpleSAML\XML\DOMDocumentFactory;
@@ -72,9 +72,9 @@ public function sign(
     /**
      * Do the actual signing of the document.
      *
-     * Note that this method does not insert the signature in the returned \DOMElement. The signature will be available
+     * Note that this method does not insert the signature in the returned \Dom\Element. The signature will be available
      * in $this->signature as a \SimpleSAML\XMLSecurity\XML\ds\Signature object, which can then be converted to XML
-     * calling toXML() on it, passing the \DOMElement value returned here as a parameter. The resulting \DOMElement
+     * calling toXML() on it, passing the \Dom\Element value returned here as a parameter. The resulting \Dom\Element
      * can then be inserted in the position desired.
      *
      * E.g.:
@@ -82,10 +82,10 @@ public function sign(
      *     $signedXML = $this->doSign($xml);
      *     $signedXML->appendChild($this->signature->toXML($signedXML));
      *
-     * @param \DOMElement $xml The element to sign.
-     * @return \DOMElement The signed element, without the signature attached to it just yet.
+     * @param \Dom\Element $xml The element to sign.
+     * @return \Dom\Element The signed element, without the signature attached to it just yet.
      */
-    protected function doSign(DOMElement $xml): DOMElement
+    protected function doSign(Dom\Element $xml): Dom\Element
     {
         Assert::notNull(
             $this->signer,
diff --git a/src/SAML11/XML/SignedElementTrait.php b/src/SAML11/XML/SignedElementTrait.php
index 52f23bf..8d9e31a 100644
--- a/src/SAML11/XML/SignedElementTrait.php
+++ b/src/SAML11/XML/SignedElementTrait.php
@@ -10,6 +10,8 @@
 use SimpleSAML\XMLSecurity\XML\ds\Signature;
 use SimpleSAML\XMLSecurity\XML\SignedElementTrait as BaseSignedElementTrait;
 
+use function array_last;
+
 /**
  * Helper trait for processing signed elements.
  *
@@ -35,7 +37,7 @@ protected function setSignature(Signature $signature): void
         $references = $signature->getSignedInfo()->getReferences();
         Assert::count($references, 1, "A signature needs to have exactly one Reference, %d found.");
 
-        $reference = array_pop($references);
+        $reference = array_last($references);
         Assert::notNull($reference->getURI(), "URI attribute not found.", ReferenceValidationFailedException::class);
         Assert::startsWith(
             $reference->getURI()->getValue(),
diff --git a/src/SAML11/XML/saml/AbstractActionType.php b/src/SAML11/XML/saml/AbstractActionType.php
index 4ff24d1..d4cbad8 100644
--- a/src/SAML11/XML/saml/AbstractActionType.php
+++ b/src/SAML11/XML/saml/AbstractActionType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
@@ -60,7 +60,7 @@ public function getNamespace(): ?SAMLAnyURIValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -75,7 +75,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this ActionType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
         $e->textContent = strval($this->getValue());
diff --git a/src/SAML11/XML/saml/AbstractAdviceType.php b/src/SAML11/XML/saml/AbstractAdviceType.php
index de0e3ea..829b39a 100644
--- a/src/SAML11/XML/saml/AbstractAdviceType.php
+++ b/src/SAML11/XML/saml/AbstractAdviceType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\XML\Chunk;
@@ -87,16 +87,16 @@ public function isEmptyElement(): bool
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
 
         $elements = [];
         foreach ($xml->childNodes as $element) {
-            if ($element->namespaceURI === C::NS_SAML) {
+            if (!($element instanceof Dom\Element)) {
                 continue;
-            } elseif (!($element instanceof DOMElement)) {
+            } elseif ($element->namespaceURI === C::NS_SAML) {
                 continue;
             }
 
@@ -114,7 +114,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this EvidenceType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAssertionType.php b/src/SAML11/XML/saml/AbstractAssertionType.php
index d4aa909..d2e676e 100644
--- a/src/SAML11/XML/saml/AbstractAssertionType.php
+++ b/src/SAML11/XML/saml/AbstractAssertionType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Compat\ContainerSingleton;
 use SimpleSAML\SAML11\Constants as C;
@@ -27,8 +27,8 @@
 use SimpleSAML\XMLSecurity\XML\SignedElementTrait;
 
 use function array_filter;
+use function array_last;
 use function array_merge;
-use function array_pop;
 use function array_values;
 use function strval;
 
@@ -50,7 +50,7 @@ abstract class AbstractAssertionType extends AbstractSamlElement implements
     /**
      * The original signed XML
      */
-    protected DOMElement $xml;
+    protected Dom\Element $xml;
 
 
     /**
@@ -231,7 +231,7 @@ public function getAttributeStatements(): array
     /**
      * Set the XML element.
      */
-    private function setOriginalXML(DOMElement $xml): void
+    private function setOriginalXML(Dom\Element $xml): void
     {
         $this->xml = $xml;
     }
@@ -239,7 +239,7 @@ private function setOriginalXML(DOMElement $xml): void
 
     /**
      */
-    protected function getOriginalXML(): DOMElement
+    protected function getOriginalXML(): Dom\Element
     {
         return $this->xml ?? $this->toUnsignedXML();
     }
@@ -258,7 +258,7 @@ public function getBlacklistedAlgorithms(): ?array
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -294,8 +294,8 @@ public static function fromXML(DOMElement $xml): static
             self::getAttribute($xml, 'AssertionID', IDValue::class),
             self::getAttribute($xml, 'Issuer', SAMLStringValue::class),
             self::getAttribute($xml, 'IssueInstant', SAMLDateTimeValue::class),
-            array_pop($conditions),
-            array_pop($advice),
+            array_last($conditions),
+            array_last($advice),
             array_merge($statements, $subjectStatement, $authnStatement, $authzDecisionStatement, $attrStatement),
         );
 
@@ -312,7 +312,7 @@ public static function fromXML(DOMElement $xml): static
      * Convert this assertion to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
@@ -338,7 +338,7 @@ protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
      *
      * @throws \Exception
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         if ($this->isSigned() === true && $this->signer === null) {
             // We already have a signed document and no signer was set to re-sign it
@@ -362,7 +362,7 @@ public function toXML(?DOMElement $parent = null): DOMElement
                 './saml_assertion/following-sibling::*[position() = last()]',
                 XPath::getXPath($signedXML),
             );
-            $last = array_pop($assertionElements);
+            $last = array_last($assertionElements);
 
             if ($last !== null) {
                 $signedXML->insertBefore($this->signature?->toXML($signedXML), $last->nextSibling);
diff --git a/src/SAML11/XML/saml/AbstractAttributeDesignatorType.php b/src/SAML11/XML/saml/AbstractAttributeDesignatorType.php
index 6c726a3..e3bf830 100644
--- a/src/SAML11/XML/saml/AbstractAttributeDesignatorType.php
+++ b/src/SAML11/XML/saml/AbstractAttributeDesignatorType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
 
@@ -55,7 +55,7 @@ public function getAttributeNamespace(): SAMLAnyURIValue
     /**
      * Convert this AttributeDesignatorType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAttributeStatementType.php b/src/SAML11/XML/saml/AbstractAttributeStatementType.php
index 46820cb..6c26560 100644
--- a/src/SAML11/XML/saml/AbstractAttributeStatementType.php
+++ b/src/SAML11/XML/saml/AbstractAttributeStatementType.php
@@ -4,13 +4,15 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\SchemaViolationException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
+use function array_last;
+
 /**
  * SAML AttributeStatementType abstract data type.
  *
@@ -51,7 +53,7 @@ public function getAttributes(): array
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -61,7 +63,7 @@ public static function fromXML(DOMElement $xml): static
         Assert::maxCount($subject, 1, TooManyElementsException::class);
 
         return new static(
-            array_pop($subject),
+            array_last($subject),
             Attribute::getChildrenOfClass($xml),
         );
     }
@@ -70,7 +72,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AttributeStatementType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAttributeType.php b/src/SAML11/XML/saml/AbstractAttributeType.php
index 12211a2..5d206eb 100644
--- a/src/SAML11/XML/saml/AbstractAttributeType.php
+++ b/src/SAML11/XML/saml/AbstractAttributeType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
@@ -53,7 +53,7 @@ public function getAttributeValue(): array
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -69,7 +69,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AttributeType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAudienceRestrictionConditionType.php b/src/SAML11/XML/saml/AbstractAudienceRestrictionConditionType.php
index b6391f5..8da05ac 100644
--- a/src/SAML11/XML/saml/AbstractAudienceRestrictionConditionType.php
+++ b/src/SAML11/XML/saml/AbstractAudienceRestrictionConditionType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -44,7 +44,7 @@ public function getAudience(): array
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
@@ -61,7 +61,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AudienceRestrictionCondition to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAuthenticationStatementType.php b/src/SAML11/XML/saml/AbstractAuthenticationStatementType.php
index 9ca4d14..c513e99 100644
--- a/src/SAML11/XML/saml/AbstractAuthenticationStatementType.php
+++ b/src/SAML11/XML/saml/AbstractAuthenticationStatementType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
@@ -13,6 +13,8 @@
 use SimpleSAML\XMLSchema\Exception\SchemaViolationException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
+use function array_last;
+
 /**
  * SAML AuthenticationStatementType abstract data type.
  *
@@ -92,7 +94,7 @@ public function getAuthenticationInstant(): SAMLDateTimeValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -106,10 +108,10 @@ public static function fromXML(DOMElement $xml): static
         Assert::maxCount($subject, 1, TooManyElementsException::class);
 
         return new static(
-            array_pop($subject),
+            array_last($subject),
             self::getAttribute($xml, 'AuthenticationMethod', SAMLAnyURIValue::class),
             self::getAttribute($xml, 'AuthenticationInstant', SAMLDateTimeValue::class),
-            array_pop($subjectLocality),
+            array_last($subjectLocality),
             $authorityBinding,
         );
     }
@@ -118,7 +120,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AuthenticationStatementType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAuthorityBindingType.php b/src/SAML11/XML/saml/AbstractAuthorityBindingType.php
index 4586940..3ced255 100644
--- a/src/SAML11/XML/saml/AbstractAuthorityBindingType.php
+++ b/src/SAML11/XML/saml/AbstractAuthorityBindingType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -73,7 +73,7 @@ public function getBinding(): SAMLAnyURIValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -89,7 +89,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AuthorityBindingType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractAuthorizationDecisionStatementType.php b/src/SAML11/XML/saml/AbstractAuthorizationDecisionStatementType.php
index ff89a65..42f2dc0 100644
--- a/src/SAML11/XML/saml/AbstractAuthorizationDecisionStatementType.php
+++ b/src/SAML11/XML/saml/AbstractAuthorizationDecisionStatementType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\DecisionTypeValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -13,6 +13,7 @@
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 use SimpleSAML\XMLSchema\Type\AnyURIValue;
 
+use function array_last;
 use function strval;
 
 /**
@@ -96,7 +97,7 @@ public function getAction(): array
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -109,11 +110,11 @@ public static function fromXML(DOMElement $xml): static
         Assert::maxCount($evidence, 1, TooManyElementsException::class);
 
         return new static(
-            array_pop($subject),
+            array_last($subject),
             self::getAttribute($xml, 'Resource', AnyURIValue::class),
             self::getAttribute($xml, 'Decision', DecisionTypeValue::class),
             Action::getChildrenOfClass($xml),
-            array_pop($evidence),
+            array_last($evidence),
         );
     }
 
@@ -121,7 +122,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this AuthorizationDecisionStatementType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractCondition.php b/src/SAML11/XML/saml/AbstractCondition.php
index 9ee64ee..e347e28 100644
--- a/src/SAML11/XML/saml/AbstractCondition.php
+++ b/src/SAML11/XML/saml/AbstractCondition.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Utils;
@@ -63,7 +63,7 @@ public function getXsiType(): QNameValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Condition', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, C::NS_SAML, InvalidDOMElementException::class);
@@ -94,7 +94,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Condition to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
         if (!$e->lookupPrefix($this->getXsiType()->getNamespaceURI()->getValue())) {
diff --git a/src/SAML11/XML/saml/AbstractConditionsType.php b/src/SAML11/XML/saml/AbstractConditionsType.php
index cd8e6d7..8c6b728 100644
--- a/src/SAML11/XML/saml/AbstractConditionsType.php
+++ b/src/SAML11/XML/saml/AbstractConditionsType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -114,7 +114,7 @@ public function isEmptyElement(): bool
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -132,7 +132,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this ConditionsType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractDoNotCacheConditionType.php b/src/SAML11/XML/saml/AbstractDoNotCacheConditionType.php
index 2f0b36c..182a72d 100644
--- a/src/SAML11/XML/saml/AbstractDoNotCacheConditionType.php
+++ b/src/SAML11/XML/saml/AbstractDoNotCacheConditionType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 
@@ -29,7 +29,7 @@ final public function __construct()
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
@@ -41,7 +41,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this DoNotCacheCondition to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->instantiateParentElement($parent);
     }
diff --git a/src/SAML11/XML/saml/AbstractEvidenceType.php b/src/SAML11/XML/saml/AbstractEvidenceType.php
index 6eae7e6..ce4c438 100644
--- a/src/SAML11/XML/saml/AbstractEvidenceType.php
+++ b/src/SAML11/XML/saml/AbstractEvidenceType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -72,7 +72,7 @@ public function isEmptyElement(): bool
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -87,7 +87,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this EvidenceType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractNameIdentifierType.php b/src/SAML11/XML/saml/AbstractNameIdentifierType.php
index e95e95d..bdf8a0f 100644
--- a/src/SAML11/XML/saml/AbstractNameIdentifierType.php
+++ b/src/SAML11/XML/saml/AbstractNameIdentifierType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
@@ -73,7 +73,7 @@ public function getNameQualifier(): ?SAMLStringValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -89,7 +89,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this NameIdentifierType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
         $e->textContent = strval($this->getValue());
diff --git a/src/SAML11/XML/saml/AbstractStatement.php b/src/SAML11/XML/saml/AbstractStatement.php
index e3dfe99..5a19471 100644
--- a/src/SAML11/XML/saml/AbstractStatement.php
+++ b/src/SAML11/XML/saml/AbstractStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Utils;
@@ -63,7 +63,7 @@ public function getXsiType(): QNameValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Statement', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, C::NS_SAML, InvalidDOMElementException::class);
@@ -94,7 +94,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Statement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractSubjectConfirmationType.php b/src/SAML11/XML/saml/AbstractSubjectConfirmationType.php
index 98f7046..5978a0e 100644
--- a/src/SAML11/XML/saml/AbstractSubjectConfirmationType.php
+++ b/src/SAML11/XML/saml/AbstractSubjectConfirmationType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -12,6 +12,8 @@
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 use SimpleSAML\XMLSecurity\XML\ds\KeyInfo;
 
+use function array_last;
+
 /**
  * SAML SubjectConfirmationType abstract data type.
  *
@@ -75,7 +77,7 @@ public function getKeyInfo(): ?KeyInfo
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -88,8 +90,8 @@ public static function fromXML(DOMElement $xml): static
 
         return new static(
             ConfirmationMethod::getChildrenOfClass($xml),
-            array_pop($subjectConfirmationData),
-            array_pop($keyInfo),
+            array_last($subjectConfirmationData),
+            array_last($keyInfo),
         );
     }
 
@@ -97,7 +99,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this SubjectConfirmationType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractSubjectLocalityType.php b/src/SAML11/XML/saml/AbstractSubjectLocalityType.php
index bf5a7ac..4410dd8 100644
--- a/src/SAML11/XML/saml/AbstractSubjectLocalityType.php
+++ b/src/SAML11/XML/saml/AbstractSubjectLocalityType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -69,7 +69,7 @@ public function isEmptyElement(): bool
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -84,7 +84,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this SubjectLocalityType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractSubjectStatement.php b/src/SAML11/XML/saml/AbstractSubjectStatement.php
index 1038b22..2a1417d 100644
--- a/src/SAML11/XML/saml/AbstractSubjectStatement.php
+++ b/src/SAML11/XML/saml/AbstractSubjectStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Utils;
@@ -19,6 +19,8 @@
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
+use function array_last;
+
 /**
  * Class implementing the <saml:SubjectStatement> extension point.
  *
@@ -60,7 +62,7 @@ public function getXsiType(): QNameValue
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'SubjectStatement', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, C::NS_SAML, InvalidDOMElementException::class);
@@ -80,7 +82,7 @@ public static function fromXML(DOMElement $xml): static
             Assert::maxCount($subject, 1, TooManyElementsException::class);
 
             // we don't have a handler, proceed with unknown SubjectStatement
-            return new UnknownSubjectStatement(new Chunk($xml), $type, array_pop($subject));
+            return new UnknownSubjectStatement(new Chunk($xml), $type, array_last($subject));
         }
 
         Assert::subclassOf(
@@ -95,7 +97,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this SubjectStatement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractSubjectStatementType.php b/src/SAML11/XML/saml/AbstractSubjectStatementType.php
index c57e4e8..38fb57e 100644
--- a/src/SAML11/XML/saml/AbstractSubjectStatementType.php
+++ b/src/SAML11/XML/saml/AbstractSubjectStatementType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 
 /**
  * @package simplesamlphp\saml11
@@ -36,7 +36,7 @@ public function getSubject(): Subject
     /**
      * Convert this SubjectStatement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AbstractSubjectType.php b/src/SAML11/XML/saml/AbstractSubjectType.php
index a99d4b1..b5d33db 100644
--- a/src/SAML11/XML/saml/AbstractSubjectType.php
+++ b/src/SAML11/XML/saml/AbstractSubjectType.php
@@ -4,12 +4,14 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
+use function array_last;
+
 /**
  * SAML SubjectType abstract data type.
  *
@@ -61,7 +63,7 @@ public function getNameIdentifier(): ?NameIdentifier
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -73,8 +75,8 @@ public static function fromXML(DOMElement $xml): static
         Assert::maxCount($nameIdentifier, 1, TooManyElementsException::class);
 
         return new static(
-            array_pop($subjectConfirmation),
-            array_pop($nameIdentifier),
+            array_last($subjectConfirmation),
+            array_last($nameIdentifier),
         );
     }
 
@@ -82,7 +84,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this SubjectType to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/AttributeDesignator.php b/src/SAML11/XML/saml/AttributeDesignator.php
index 069a6af..9275cd2 100644
--- a/src/SAML11/XML/saml/AttributeDesignator.php
+++ b/src/SAML11/XML/saml/AttributeDesignator.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
@@ -28,7 +28,7 @@ final class AttributeDesignator extends AbstractAttributeDesignatorType implemen
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
diff --git a/src/SAML11/XML/saml/AttributeValue.php b/src/SAML11/XML/saml/AttributeValue.php
index fe948cd..3a70f40 100644
--- a/src/SAML11/XML/saml/AttributeValue.php
+++ b/src/SAML11/XML/saml/AttributeValue.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
@@ -37,7 +37,7 @@ class AttributeValue extends AbstractSamlElement implements SchemaValidatableEle
      * Create an AttributeValue.
      *
      * @param \SimpleSAML\XMLSchema\Type\Interface\ValueTypeInterface|\SimpleSAML\XML\AbstractElement $value
-     * @throws \SimpleSAML\Assert\AssertionFailedException if the supplied value is neither a string or a DOMElement
+     * @throws \SimpleSAML\Assert\AssertionFailedException if the supplied value is neither a string or a Dom\Element
      */
     final public function __construct(
         protected SAMLStringValue|IntegerValue|SAMLDateTimeValue|AbstractElement $value,
@@ -89,7 +89,7 @@ public function getValue()
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -139,7 +139,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Append this attribute value to an element.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/saml/SubjectConfirmationData.php b/src/SAML11/XML/saml/SubjectConfirmationData.php
index 90e2df9..80e5209 100644
--- a/src/SAML11/XML/saml/SubjectConfirmationData.php
+++ b/src/SAML11/XML/saml/SubjectConfirmationData.php
@@ -4,15 +4,18 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
+use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Type\SAMLStringValue;
 use SimpleSAML\XML\AbstractElement;
+use SimpleSAML\XML\Attribute as XMLAttribute;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XML\SchemaValidatableElementInterface;
 use SimpleSAML\XML\SchemaValidatableElementTrait;
 use SimpleSAML\XMLSchema\Constants as C_XSI;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
+use SimpleSAML\XMLSchema\Type\AnyURIValue;
 use SimpleSAML\XMLSchema\Type\IntegerValue;
 use SimpleSAML\XMLSchema\Type\Interface\ValueTypeInterface;
 
@@ -41,7 +44,7 @@ class SubjectConfirmationData extends AbstractSamlElement implements SchemaValid
      *  - null
      *  - \SimpleSAML\XML\AbstractElement
      *
-     * @throws \SimpleSAML\Assert\AssertionFailedException if the supplied value is neither a string or a DOMElement
+     * @throws \SimpleSAML\Assert\AssertionFailedException if the supplied value is neither a string or a Dom\Element
      */
     final public function __construct(
         protected SAMLStringValue|IntegerValue|null|AbstractElement $value,
@@ -92,7 +95,7 @@ public function getValue(): SAMLStringValue|IntegerValue|AbstractElement|null
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
@@ -136,7 +139,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Append this attribute value to an element.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::instantiateParentElement($parent);
 
@@ -146,21 +149,41 @@ public function toXML(?DOMElement $parent = null): DOMElement
         switch ($type) {
             case "integer":
                 // make sure that the xs namespace is available in the SubjectConfirmationData
-                $e->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xsi', C_XSI::NS_XSI);
-                $e->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xs', C_XSI::NS_XS);
+                $xsi_attr = new XMLAttribute(C::NS_XMLNS, 'xmlns', 'xsi', AnyURIValue::fromString(C_XSI::NS_XSI));
+                $xsi_attr->toXML($e);
+
+                $xs_attr = new XMLAttribute(C::NS_XMLNS, 'xmlns', 'xs', AnyURIValue::fromString(C_XSI::NS_XS));
+                $xs_attr->toXML($e);
+
                 $e->setAttributeNS(C_XSI::NS_XSI, 'xsi:type', 'xs:integer');
                 $e->textContent = strval($value);
                 break;
             case "NULL":
-                $e->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xsi', C_XSI::NS_XSI);
+                $xs_attr = new XMLAttribute(C::NS_XMLNS, 'xmlns', 'xs', AnyURIValue::fromString(C_XSI::NS_XS));
+                $xs_attr->toXML($e);
+
                 $e->setAttributeNS(C_XSI::NS_XSI, 'xsi:nil', '1');
                 $e->textContent = '';
                 break;
             case "object":
                 if ($value instanceof ValueTypeInterface) {
                     if ($this->value instanceof IntegerValue) {
-                        $e->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xsi', C_XSI::NS_XSI);
-                        $e->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xs', C_XSI::NS_XS);
+                        $xsi_attr = new XMLAttribute(
+                            C::NS_XMLNS,
+                            'xmlns',
+                            'xsi',
+                            AnyURIValue::fromString(C_XSI::NS_XSI),
+                        );
+                        $xsi_attr->toXML($e);
+
+                        $xs_attr = new XMLAttribute(
+                            C::NS_XMLNS,
+                            'xmlns',
+                            'xs',
+                            AnyURIValue::fromString(C_XSI::NS_XS),
+                        );
+                        $xs_attr->toXML($e);
+
                         $e->setAttributeNS(C_XSI::NS_XSI, 'xsi:type', 'xs:integer');
                     }
                     $e->textContent = strval($value);
diff --git a/src/SAML11/XML/saml/UnknownCondition.php b/src/SAML11/XML/saml/UnknownCondition.php
index 1a02db0..106cbc8 100644
--- a/src/SAML11/XML/saml/UnknownCondition.php
+++ b/src/SAML11/XML/saml/UnknownCondition.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
@@ -41,7 +41,7 @@ public function getRawCondition(): Chunk
     /**
      * Convert this unknown condition to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->getRawCondition()->toXML($parent);
     }
diff --git a/src/SAML11/XML/saml/UnknownStatement.php b/src/SAML11/XML/saml/UnknownStatement.php
index aa64f44..3024491 100644
--- a/src/SAML11/XML/saml/UnknownStatement.php
+++ b/src/SAML11/XML/saml/UnknownStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
@@ -41,7 +41,7 @@ public function getRawStatement(): Chunk
     /**
      * Convert this unknown statement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->getRawStatement()->toXML($parent);
     }
diff --git a/src/SAML11/XML/saml/UnknownSubjectStatement.php b/src/SAML11/XML/saml/UnknownSubjectStatement.php
index 679c1d2..e5b33cc 100644
--- a/src/SAML11/XML/saml/UnknownSubjectStatement.php
+++ b/src/SAML11/XML/saml/UnknownSubjectStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\saml;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
@@ -42,7 +42,7 @@ public function getRawSubjectStatement(): Chunk
     /**
      * Convert this unknown SubjectStatement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->getRawSubjectStatement()->toXML($parent);
     }
diff --git a/src/SAML11/XML/samlp/AbstractAttributeQueryType.php b/src/SAML11/XML/samlp/AbstractAttributeQueryType.php
index f90aaa7..2c6b538 100644
--- a/src/SAML11/XML/samlp/AbstractAttributeQueryType.php
+++ b/src/SAML11/XML/samlp/AbstractAttributeQueryType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\saml\AttributeDesignator;
 use SimpleSAML\SAML11\XML\saml\Subject;
@@ -59,7 +59,7 @@ public function getAttributeDesignator(): array
     /**
      * Convert this AttributeQuery to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractAuthenticationQueryType.php b/src/SAML11/XML/samlp/AbstractAuthenticationQueryType.php
index 77c21b5..2178857 100644
--- a/src/SAML11/XML/samlp/AbstractAuthenticationQueryType.php
+++ b/src/SAML11/XML/samlp/AbstractAuthenticationQueryType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\XML\saml\Subject;
 
@@ -43,7 +43,7 @@ public function getAuthenticationMethod(): SAMLAnyURIValue
     /**
      * Convert this AuthenticationQuery to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
         $e->setAttribute('AuthenticationMethod', strval($this->getAuthenticationMethod()));
diff --git a/src/SAML11/XML/samlp/AbstractAuthorizationDecisionQueryType.php b/src/SAML11/XML/samlp/AbstractAuthorizationDecisionQueryType.php
index f099f99..2a956af 100644
--- a/src/SAML11/XML/samlp/AbstractAuthorizationDecisionQueryType.php
+++ b/src/SAML11/XML/samlp/AbstractAuthorizationDecisionQueryType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\XML\saml\Action;
@@ -73,7 +73,7 @@ public function getAction(): array
     /**
      * Convert this AttributeQuery to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
         $e->setAttribute('Resource', strval($this->getResource()));
diff --git a/src/SAML11/XML/samlp/AbstractMessage.php b/src/SAML11/XML/samlp/AbstractMessage.php
index dfabbb2..af4af0d 100644
--- a/src/SAML11/XML/samlp/AbstractMessage.php
+++ b/src/SAML11/XML/samlp/AbstractMessage.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\SAML11\XML\CanonicalizableElementTrait;
 use SimpleSAML\SAML11\XML\SignableElementTrait;
@@ -41,7 +41,7 @@ abstract class AbstractMessage extends AbstractSamlpElement implements
     /**
      * The original signed XML
      */
-    protected DOMElement $xml;
+    protected Dom\Element $xml;
 
 
     /**
@@ -106,7 +106,7 @@ public function isMessageConstructedWithSignature(): bool
     /**
      * Get the XML element.
      */
-    public function getXML(): DOMElement
+    public function getXML(): Dom\Element
     {
         return $this->xml;
     }
@@ -115,7 +115,7 @@ public function getXML(): DOMElement
     /**
      * Set the XML element.
      */
-    protected function setXML(DOMElement $xml): void
+    protected function setXML(Dom\Element $xml): void
     {
         $this->xml = $xml;
     }
@@ -123,7 +123,7 @@ protected function setXML(DOMElement $xml): void
 
     /**
      */
-    protected function getOriginalXML(): DOMElement
+    protected function getOriginalXML(): Dom\Element
     {
         return $this->xml ?? $this->toUnsignedXML();
     }
@@ -133,7 +133,7 @@ protected function getOriginalXML(): DOMElement
      * Convert this message to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractQuery.php b/src/SAML11/XML/samlp/AbstractQuery.php
index 87f9084..8328b9b 100644
--- a/src/SAML11/XML/samlp/AbstractQuery.php
+++ b/src/SAML11/XML/samlp/AbstractQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Utils;
@@ -52,7 +52,7 @@ protected function __construct(
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Query', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, C::NS_SAMLP, InvalidDOMElementException::class);
@@ -83,7 +83,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Query to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractRequestAbstractType.php b/src/SAML11/XML/samlp/AbstractRequestAbstractType.php
index cd7b0d5..7a35655 100644
--- a/src/SAML11/XML/samlp/AbstractRequestAbstractType.php
+++ b/src/SAML11/XML/samlp/AbstractRequestAbstractType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\SAML11\Utils\XPath;
@@ -12,7 +12,7 @@
 use SimpleSAML\XMLSchema\Type\IDValue;
 use SimpleSAML\XMLSchema\Type\NonNegativeIntegerValue;
 
-use function array_pop;
+use function array_last;
 use function strval;
 
 /**
@@ -70,7 +70,7 @@ public function getRespondWith(): array
      * Convert this message to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toUnsignedXML($parent);
         $e->setAttribute('RequestID', strval($this->getID()));
@@ -86,7 +86,7 @@ protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
     /**
      * Create XML from this class
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         if ($this->isSigned() === true && $this->signer === null) {
             // We already have a signed document and no signer was set to re-sign it
@@ -107,7 +107,7 @@ public function toXML(?DOMElement $parent = null): DOMElement
 
             // Test for an RespondWith
             $messageElements = XPath::xpQuery($signedXML, './saml_protocol:RespondWith', XPath::getXPath($signedXML));
-            $respondWith = array_pop($messageElements);
+            $respondWith = array_last($messageElements);
 
             if ($respondWith === null) {
                 $signedXML->appendChild($this->signature?->toXML($signedXML));
diff --git a/src/SAML11/XML/samlp/AbstractRequestType.php b/src/SAML11/XML/samlp/AbstractRequestType.php
index f979133..ef9b829 100644
--- a/src/SAML11/XML/samlp/AbstractRequestType.php
+++ b/src/SAML11/XML/samlp/AbstractRequestType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\SAML11\XML\saml\AssertionIDReference;
@@ -12,7 +12,7 @@
 use SimpleSAML\XMLSchema\Type\IDValue;
 use SimpleSAML\XMLSchema\Type\NonNegativeIntegerValue;
 
-use function array_pop;
+use function array_last;
 use function is_array;
 
 /**
@@ -49,7 +49,7 @@ protected function __construct(
         if (is_array($request)) {
             Assert::minCount($request, 1, SchemaViolationException::class);
 
-            $req = array_pop($request);
+            $req = array_last($request);
             if ($req instanceof AssertionIDReference) {
                 Assert::allIsInstanceOf($request, AssertionIDReference::class, SchemaViolationException::class);
             } elseif ($req instanceof AssertionArtifact) {
@@ -82,7 +82,7 @@ public function getRequest(): AbstractQueryAbstractType|array
      * Convert this message to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toUnsignedXML($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractResponseAbstractType.php b/src/SAML11/XML/samlp/AbstractResponseAbstractType.php
index c67f6c5..881d552 100644
--- a/src/SAML11/XML/samlp/AbstractResponseAbstractType.php
+++ b/src/SAML11/XML/samlp/AbstractResponseAbstractType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
 use SimpleSAML\XMLSchema\Type\IDValue;
 use SimpleSAML\XMLSchema\Type\NonNegativeIntegerValue;
@@ -56,7 +56,7 @@ public function getID(): IDValue
      * Convert this message to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toUnsignedXML($parent);
         $e->setAttribute('ResponseID', strval($this->getId()));
@@ -68,7 +68,7 @@ protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
     /**
      * Create XML from this class
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         if ($this->isSigned() === true && $this->signer === null) {
             // We already have a signed document and no signer was set to re-sign it
diff --git a/src/SAML11/XML/samlp/AbstractResponseType.php b/src/SAML11/XML/samlp/AbstractResponseType.php
index ea2e7f0..b504d88 100644
--- a/src/SAML11/XML/samlp/AbstractResponseType.php
+++ b/src/SAML11/XML/samlp/AbstractResponseType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
@@ -102,7 +102,7 @@ public function getStatus(): Status
      * Convert this message to an unsigned XML document.
      * This method does not sign the resulting XML document.
      */
-    protected function toUnsignedXML(?DOMElement $parent = null): DOMElement
+    protected function toUnsignedXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toUnsignedXML($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractStatusCodeType.php b/src/SAML11/XML/samlp/AbstractStatusCodeType.php
index 1994075..bd76338 100644
--- a/src/SAML11/XML/samlp/AbstractStatusCodeType.php
+++ b/src/SAML11/XML/samlp/AbstractStatusCodeType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -65,7 +65,7 @@ public function getSubCodes(): array
      * @throws \SimpleSAML\XML\Exception\MissingAttributeException
      *   if the supplied element is missing one of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'StatusCode', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, StatusCode::NS, InvalidDOMElementException::class);
@@ -83,7 +83,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this StatusCode to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
         $e->setAttribute('Value', strval($this->getValue()));
diff --git a/src/SAML11/XML/samlp/AbstractStatusDetailType.php b/src/SAML11/XML/samlp/AbstractStatusDetailType.php
index 9740715..299196d 100644
--- a/src/SAML11/XML/samlp/AbstractStatusDetailType.php
+++ b/src/SAML11/XML/samlp/AbstractStatusDetailType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XML\ExtendableElementTrait;
@@ -51,14 +51,14 @@ public function isEmptyElement(): bool
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'StatusDetail', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, StatusDetail::NS, InvalidDOMElementException::class);
 
         $details = [];
         foreach ($xml->childNodes as $detail) {
-            if (!($detail instanceof DOMElement)) {
+            if (!($detail instanceof Dom\Element)) {
                 continue;
             }
 
@@ -72,7 +72,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this StatusDetail to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractStatusType.php b/src/SAML11/XML/samlp/AbstractStatusType.php
index 66f88d2..d7acc82 100644
--- a/src/SAML11/XML/samlp/AbstractStatusType.php
+++ b/src/SAML11/XML/samlp/AbstractStatusType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Exception\ProtocolViolationException;
@@ -12,7 +12,7 @@
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
-use function array_pop;
+use function array_last;
 
 /**
  * SAML Status data type.
@@ -85,7 +85,7 @@ public function getStatusDetail(): ?StatusDetail
      * @throws \SimpleSAML\XML\Exception\MissingElementException
      *   if one of the mandatory child-elements is missing
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Status', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, Status::NS, InvalidDOMElementException::class);
@@ -100,9 +100,9 @@ public static function fromXML(DOMElement $xml): static
         $statusDetail = StatusDetail::getChildrenOfClass($xml);
 
         return new static(
-            array_pop($statusCode),
-            array_pop($statusMessage),
-            array_pop($statusDetail),
+            array_last($statusCode),
+            array_last($statusMessage),
+            array_last($statusDetail),
         );
     }
 
@@ -110,7 +110,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Status to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/samlp/AbstractSubjectQuery.php b/src/SAML11/XML/samlp/AbstractSubjectQuery.php
index 6d668b5..f736809 100644
--- a/src/SAML11/XML/samlp/AbstractSubjectQuery.php
+++ b/src/SAML11/XML/samlp/AbstractSubjectQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Constants as C;
 use SimpleSAML\SAML11\Utils;
@@ -21,7 +21,7 @@
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
-use function array_pop;
+use function array_last;
 
 /**
  * SAMLP Query data type.
@@ -58,7 +58,7 @@ protected function __construct(
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'SubjectQuery', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, C::NS_SAMLP, InvalidDOMElementException::class);
@@ -78,7 +78,7 @@ public static function fromXML(DOMElement $xml): static
             Assert::maxCount($subject, 1, TooManyElementsException::class);
 
             // we don't have a handler, proceed with unknown query
-            return new UnknownSubjectQuery(new Chunk($xml), $type, array_pop($subject));
+            return new UnknownSubjectQuery(new Chunk($xml), $type, array_last($subject));
         }
 
         Assert::subclassOf(
diff --git a/src/SAML11/XML/samlp/AbstractSubjectQueryAbstractType.php b/src/SAML11/XML/samlp/AbstractSubjectQueryAbstractType.php
index 8add9cf..79a8fa2 100644
--- a/src/SAML11/XML/samlp/AbstractSubjectQueryAbstractType.php
+++ b/src/SAML11/XML/samlp/AbstractSubjectQueryAbstractType.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\XML\saml\Subject;
 
 /**
@@ -37,7 +37,7 @@ public function getSubject(): Subject
     /**
      * Convert this SubjectQuery to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/SAML11/XML/samlp/AttributeQuery.php b/src/SAML11/XML/samlp/AttributeQuery.php
index 2240557..3b8eeb3 100644
--- a/src/SAML11/XML/samlp/AttributeQuery.php
+++ b/src/SAML11/XML/samlp/AttributeQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\XML\saml\AttributeDesignator;
@@ -15,7 +15,7 @@
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
-use function array_pop;
+use function array_last;
 
 /**
  * Class representing a samlp:AttributeQuery element.
@@ -33,7 +33,7 @@ final class AttributeQuery extends AbstractAttributeQueryType implements SchemaV
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'AttributeQuery', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, AttributeQuery::NS, InvalidDOMElementException::class);
@@ -46,6 +46,6 @@ public static function fromXML(DOMElement $xml): static
 
         $attributeDesignator = AttributeDesignator::getChildrenOfClass($xml);
 
-        return new static(array_pop($subject), $resource, $attributeDesignator);
+        return new static(array_last($subject), $resource, $attributeDesignator);
     }
 }
diff --git a/src/SAML11/XML/samlp/AuthenticationQuery.php b/src/SAML11/XML/samlp/AuthenticationQuery.php
index 9d9f28a..3a8d45e 100644
--- a/src/SAML11/XML/samlp/AuthenticationQuery.php
+++ b/src/SAML11/XML/samlp/AuthenticationQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\XML\saml\Subject;
@@ -14,7 +14,7 @@
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
-use function array_pop;
+use function array_last;
 
 /**
  * Class representing a samlp:AuthenticationQuery element.
@@ -32,7 +32,7 @@ final class AuthenticationQuery extends AbstractAuthenticationQueryType implemen
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'AuthenticationQuery', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, AuthenticationQuery::NS, InvalidDOMElementException::class);
@@ -43,6 +43,6 @@ public static function fromXML(DOMElement $xml): static
         Assert::minCount($subject, 1, MissingElementException::class);
         Assert::maxCount($subject, 1, TooManyElementsException::class);
 
-        return new static(array_pop($subject), $authenticationMethod);
+        return new static(array_last($subject), $authenticationMethod);
     }
 }
diff --git a/src/SAML11/XML/samlp/AuthorizationDecisionQuery.php b/src/SAML11/XML/samlp/AuthorizationDecisionQuery.php
index 1d59e17..bfeb7b5 100644
--- a/src/SAML11/XML/samlp/AuthorizationDecisionQuery.php
+++ b/src/SAML11/XML/samlp/AuthorizationDecisionQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
 use SimpleSAML\SAML11\XML\saml\Action;
@@ -16,7 +16,7 @@
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 
-use function array_pop;
+use function array_last;
 
 /**
  * Class representing a samlp:AuthorizationDecisionQuery element.
@@ -35,7 +35,7 @@ final class AuthorizationDecisionQuery extends AbstractAuthorizationDecisionQuer
      * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'AuthorizationDecisionQuery', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, AuthorizationDecisionQuery::NS, InvalidDOMElementException::class);
@@ -52,6 +52,6 @@ public static function fromXML(DOMElement $xml): static
         $evidence = Evidence::getChildrenOfClass($xml);
         Assert::maxCount($evidence, 1, TooManyElementsException::class);
 
-        return new static(array_pop($subject), $resource, array_pop($evidence), $action);
+        return new static(array_last($subject), $resource, array_last($evidence), $action);
     }
 }
diff --git a/src/SAML11/XML/samlp/Request.php b/src/SAML11/XML/samlp/Request.php
index aa516f4..de8a9d5 100644
--- a/src/SAML11/XML/samlp/Request.php
+++ b/src/SAML11/XML/samlp/Request.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\Exception\VersionMismatchException;
 use SimpleSAML\SAML11\Type\SAMLDateTimeValue;
@@ -15,8 +15,8 @@
 use SimpleSAML\XMLSchema\Type\IDValue;
 use SimpleSAML\XMLSchema\Type\NonNegativeIntegerValue;
 
+use function array_last;
 use function array_merge;
-use function array_pop;
 
 /**
  * Class representing a samlp:Request element.
@@ -35,7 +35,7 @@ final class Request extends AbstractRequestType
      * @throws \SimpleSAML\XML\Exception\MissingElementException
      *   if one of the mandatory child-elements is missing
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Request', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, Request::NS, InvalidDOMElementException::class);
@@ -85,7 +85,7 @@ public static function fromXML(DOMElement $xml): static
         $issueInstant = self::getAttribute($xml, 'IssueInstant', SAMLDateTimeValue::class);
 
         return new static(
-            $assertionIdReference ?: $assertionArtifact ?: array_pop($query),
+            $assertionIdReference ?: $assertionArtifact ?: array_last($query),
             self::getAttribute($xml, 'RequestID', IDValue::class),
             $majorVersion,
             $minorVersion,
diff --git a/src/SAML11/XML/samlp/Response.php b/src/SAML11/XML/samlp/Response.php
index fcbc95d..66b025c 100644
--- a/src/SAML11/XML/samlp/Response.php
+++ b/src/SAML11/XML/samlp/Response.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\Assert\Assert;
 use SimpleSAML\SAML11\Exception\VersionMismatchException;
 use SimpleSAML\SAML11\Type\SAMLAnyURIValue;
@@ -20,7 +20,7 @@
 use SimpleSAML\XMLSchema\Type\NCNameValue;
 use SimpleSAML\XMLSchema\Type\NonNegativeIntegerValue;
 
-use function array_pop;
+use function array_last;
 
 /**
  * Class representing a samlp:Response element.
@@ -42,7 +42,7 @@ final class Response extends AbstractResponseType implements SchemaValidatableEl
      * @throws \SimpleSAML\XML\Exception\MissingElementException
      *   if one of the mandatory child-elements is missing
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Response', InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, Response::NS, InvalidDOMElementException::class);
@@ -61,7 +61,7 @@ public static function fromXML(DOMElement $xml): static
             $majorVersion,
             $minorVersion,
             self::getAttribute($xml, 'ResponseID', IDValue::class),
-            array_pop($status),
+            array_last($status),
             self::getAttribute($xml, 'IssueInstant', SAMLDateTimeValue::class),
             Assertion::getChildrenOfClass($xml),
             self::getOptionalAttribute($xml, 'InResponseTo', NCNameValue::class, null),
diff --git a/src/SAML11/XML/samlp/UnknownQuery.php b/src/SAML11/XML/samlp/UnknownQuery.php
index b3436d0..3e43ac1 100644
--- a/src/SAML11/XML/samlp/UnknownQuery.php
+++ b/src/SAML11/XML/samlp/UnknownQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
@@ -41,7 +41,7 @@ public function getRawQuery(): Chunk
     /**
      * Convert this unknown query to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->getRawQuery()->toXML($parent);
     }
diff --git a/src/SAML11/XML/samlp/UnknownSubjectQuery.php b/src/SAML11/XML/samlp/UnknownSubjectQuery.php
index b9611d6..c33e61c 100644
--- a/src/SAML11/XML/samlp/UnknownSubjectQuery.php
+++ b/src/SAML11/XML/samlp/UnknownSubjectQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\SAML11\XML\samlp;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\SAML11\XML\saml\Subject;
 use SimpleSAML\XML\Chunk;
 use SimpleSAML\XMLSchema\Type\QNameValue;
@@ -43,7 +43,7 @@ public function getRawSubjectQuery(): Chunk
     /**
      * Convert this unknown subject query to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         return $this->getRawSubjectQuery()->toXML($parent);
     }
diff --git a/tests/bin/signedassertion.php b/tests/bin/signedassertion.php
index 3677c22..bb48bbd 100644
--- a/tests/bin/signedassertion.php
+++ b/tests/bin/signedassertion.php
@@ -21,4 +21,8 @@
 
 $unsignedAssertion = Assertion::fromXML($document->documentElement);
 $unsignedAssertion->sign($signer);
-echo $unsignedAssertion->toXML()->ownerDocument->saveXML();
+
+/** @var \Dom\XMLDocument $ownerDocument */
+$ownerDocument = $unsignedAssertion->toXML()->ownerDocument;
+
+echo $ownerDocument->saveXML();
diff --git a/tests/resources/schemas/simplesamlphp.xsd b/tests/resources/schemas/simplesamlphp.xsd
index 56e6f00..09700f0 100644
--- a/tests/resources/schemas/simplesamlphp.xsd
+++ b/tests/resources/schemas/simplesamlphp.xsd
@@ -1,17 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!DOCTYPE schema
-  PUBLIC "-//W3C//DTD XMLSchema 200102//EN" "http://www.w3.org/2001/XMLSchema.dtd"
- [
-   <!ATTLIST schema 
-     xmlns:ds CDATA #FIXED "urn:x-simplesamlphp:namespace">
-   <!ENTITY ssp 'urn:x-simplesamlphp:namespace'>
-   <!ENTITY % p ''>
-   <!ENTITY % s ''>
-  ]>
 
 <!-- Schema for SimpleSAMLphp dummy classes -->
 
-
 <schema xmlns="http://www.w3.org/2001/XMLSchema"
         xmlns:ssp="urn:x-simplesamlphp:namespace"
         xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion"
diff --git a/tests/resources/xml/saml_Advice.xml b/tests/resources/xml/saml_Advice.xml
index f387127..62cfe7c 100644
--- a/tests/resources/xml/saml_Advice.xml
+++ b/tests/resources/xml/saml_Advice.xml
@@ -62,7 +62,7 @@
             </saml:SubjectConfirmation>
           </saml:Subject>
           <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-          <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+          <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
         </saml:AuthenticationStatement>
         <saml:AttributeStatement>
           <saml:Subject>
@@ -129,7 +129,7 @@
         </saml:SubjectConfirmation>
       </saml:Subject>
       <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-      <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+      <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
     </saml:AuthenticationStatement>
     <saml:AttributeStatement>
       <saml:Subject>
diff --git a/tests/resources/xml/saml_Assertion.xml b/tests/resources/xml/saml_Assertion.xml
index 55ce644..c7592ca 100644
--- a/tests/resources/xml/saml_Assertion.xml
+++ b/tests/resources/xml/saml_Assertion.xml
@@ -72,7 +72,7 @@
               </saml:SubjectConfirmation>
             </saml:Subject>
             <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-            <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+            <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
           </saml:AuthenticationStatement>
           <saml:AttributeStatement>
             <saml:Subject>
@@ -139,7 +139,7 @@
           </saml:SubjectConfirmation>
         </saml:Subject>
         <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-        <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+        <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
       </saml:AuthenticationStatement>
       <saml:AttributeStatement>
         <saml:Subject>
@@ -206,7 +206,7 @@
       </saml:SubjectConfirmation>
     </saml:Subject>
     <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-    <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+    <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
   </saml:AuthenticationStatement>
   <saml:AuthorizationDecisionStatement Resource="urn:x-simplesamlphp:resource" Decision="Permit">
     <saml:Subject>
@@ -278,7 +278,7 @@
             </saml:SubjectConfirmation>
           </saml:Subject>
           <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-          <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+          <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
         </saml:AuthenticationStatement>
         <saml:AttributeStatement>
           <saml:Subject>
diff --git a/tests/resources/xml/saml_AuthenticationStatement.xml b/tests/resources/xml/saml_AuthenticationStatement.xml
index f6777e6..480f369 100644
--- a/tests/resources/xml/saml_AuthenticationStatement.xml
+++ b/tests/resources/xml/saml_AuthenticationStatement.xml
@@ -16,5 +16,5 @@
     </saml:SubjectConfirmation>
   </saml:Subject>
   <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-  <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+  <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
 </saml:AuthenticationStatement>
diff --git a/tests/resources/xml/saml_AuthorityBinding.xml b/tests/resources/xml/saml_AuthorityBinding.xml
index 8d15770..9a553bf 100644
--- a/tests/resources/xml/saml_AuthorityBinding.xml
+++ b/tests/resources/xml/saml_AuthorityBinding.xml
@@ -1 +1 @@
-<saml:AuthorityBinding xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+<saml:AuthorityBinding xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
diff --git a/tests/resources/xml/saml_AuthorizationDecisionStatement.xml b/tests/resources/xml/saml_AuthorizationDecisionStatement.xml
index 7ab7b9c..c5f69e0 100644
--- a/tests/resources/xml/saml_AuthorizationDecisionStatement.xml
+++ b/tests/resources/xml/saml_AuthorizationDecisionStatement.xml
@@ -68,7 +68,7 @@
           </saml:SubjectConfirmation>
         </saml:Subject>
         <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-        <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+        <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
       </saml:AuthenticationStatement>
       <saml:AttributeStatement>
         <saml:Subject>
diff --git a/tests/resources/xml/saml_Evidence.xml b/tests/resources/xml/saml_Evidence.xml
index 84740a8..ba39915 100644
--- a/tests/resources/xml/saml_Evidence.xml
+++ b/tests/resources/xml/saml_Evidence.xml
@@ -13,13 +13,13 @@
     <saml:Statement xmlns:ssp="urn:x-simplesamlphp:namespace" xsi:type="ssp:CustomStatementType">
       <saml:Audience>urn:some:audience</saml:Audience>
     </saml:Statement>
-    <saml:SubjectStatement xsi:type="ssp:CustomSubjectStatementType">
+    <saml:SubjectStatement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ssp:CustomSubjectStatementType">
       <saml:Subject>
         <saml:NameIdentifier NameQualifier="TheNameQualifier" Format="urn:the:format">TheNameIDValue</saml:NameIdentifier>
         <saml:SubjectConfirmation>
           <saml:ConfirmationMethod>_Test1</saml:ConfirmationMethod>
           <saml:ConfirmationMethod>_Test2</saml:ConfirmationMethod>
-          <saml:SubjectConfirmationData xsi:type="xs:integer">2</saml:SubjectConfirmationData>
+          <saml:SubjectConfirmationData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
           <ds:KeyInfo Id="EvidenceSubjectStatementID">
             <ds:KeyName>testkey</ds:KeyName>
             <ds:X509Data>
@@ -38,7 +38,7 @@
         <saml:SubjectConfirmation>
           <saml:ConfirmationMethod>_Test1</saml:ConfirmationMethod>
           <saml:ConfirmationMethod>_Test2</saml:ConfirmationMethod>
-          <saml:SubjectConfirmationData xsi:type="xs:integer">2</saml:SubjectConfirmationData>
+          <saml:SubjectConfirmationData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
           <ds:KeyInfo Id="EvidenceAuthenticationStatementID">
             <ds:KeyName>testkey</ds:KeyName>
             <ds:X509Data>
@@ -50,7 +50,7 @@
         </saml:SubjectConfirmation>
       </saml:Subject>
       <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-      <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+      <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
     </saml:AuthenticationStatement>
     <saml:AttributeStatement>
       <saml:Subject>
@@ -58,7 +58,7 @@
         <saml:SubjectConfirmation>
           <saml:ConfirmationMethod>_Test1</saml:ConfirmationMethod>
           <saml:ConfirmationMethod>_Test2</saml:ConfirmationMethod>
-          <saml:SubjectConfirmationData xsi:type="xs:integer">2</saml:SubjectConfirmationData>
+          <saml:SubjectConfirmationData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
           <ds:KeyInfo Id="EvidenceAttributeStatementID">
             <ds:KeyName>testkey</ds:KeyName>
             <ds:X509Data>
diff --git a/tests/resources/xml/saml_Statement.xml b/tests/resources/xml/saml_Statement.xml
index 84f9724..bc8cdad 100644
--- a/tests/resources/xml/saml_Statement.xml
+++ b/tests/resources/xml/saml_Statement.xml
@@ -1,3 +1,3 @@
-<saml:Statement xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ssp:CustomStatementType">
+<saml:Statement xsi:type="ssp:CustomStatementType" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <saml:Audience>urn:some:audience</saml:Audience>
 </saml:Statement>
diff --git a/tests/resources/xml/saml_Subject.xml b/tests/resources/xml/saml_Subject.xml
index 735f58d..4d6dedd 100644
--- a/tests/resources/xml/saml_Subject.xml
+++ b/tests/resources/xml/saml_Subject.xml
@@ -1,4 +1,4 @@
-<saml:Subject xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ssp="urn:x-simplesamlphp:namespace">
+<saml:Subject xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <saml:NameIdentifier NameQualifier="TheNameQualifier" Format="urn:the:format">TheNameIDValue</saml:NameIdentifier>
   <saml:SubjectConfirmation>
     <saml:ConfirmationMethod>_Test1</saml:ConfirmationMethod>
diff --git a/tests/resources/xml/saml_SubjectConfirmationData.xml b/tests/resources/xml/saml_SubjectConfirmationData.xml
index 98262f0..c53dbed 100644
--- a/tests/resources/xml/saml_SubjectConfirmationData.xml
+++ b/tests/resources/xml/saml_SubjectConfirmationData.xml
@@ -1 +1 @@
-<saml:SubjectConfirmationData xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
+<saml:SubjectConfirmationData xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
diff --git a/tests/resources/xml/saml_SubjectStatement.xml b/tests/resources/xml/saml_SubjectStatement.xml
index 36b755a..8fb7788 100644
--- a/tests/resources/xml/saml_SubjectStatement.xml
+++ b/tests/resources/xml/saml_SubjectStatement.xml
@@ -1,4 +1,4 @@
-<saml:SubjectStatement xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="ssp:CustomSubjectStatementType">
+<saml:SubjectStatement xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ssp:CustomSubjectStatementType" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
   <saml:Subject>
     <saml:NameIdentifier NameQualifier="TheNameQualifier" Format="urn:the:format">TheNameIDValue</saml:NameIdentifier>
     <saml:SubjectConfirmation>
diff --git a/tests/resources/xml/samlp_AuthorizationDecisionQuery.xml b/tests/resources/xml/samlp_AuthorizationDecisionQuery.xml
index 867bd70..aeb5f29 100644
--- a/tests/resources/xml/samlp_AuthorizationDecisionQuery.xml
+++ b/tests/resources/xml/samlp_AuthorizationDecisionQuery.xml
@@ -43,7 +43,7 @@
           </saml:SubjectConfirmation>
         </saml:Subject>
         <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-        <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+        <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
       </saml:AuthenticationStatement>
       <saml:AttributeStatement>
         <saml:Subject>
@@ -51,7 +51,7 @@
           <saml:SubjectConfirmation>
             <saml:ConfirmationMethod>_Test1</saml:ConfirmationMethod>
             <saml:ConfirmationMethod>_Test2</saml:ConfirmationMethod>
-            <saml:SubjectConfirmationData xsi:type="xs:integer">2</saml:SubjectConfirmationData>
+            <saml:SubjectConfirmationData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:integer">2</saml:SubjectConfirmationData>
             <ds:KeyInfo Id="AttributeStatementID">
               <ds:KeyName>testkey</ds:KeyName>
               <ds:X509Data>
diff --git a/tests/resources/xml/samlp_Query.xml b/tests/resources/xml/samlp_Query.xml
index 9572d6b..9245a0b 100644
--- a/tests/resources/xml/samlp_Query.xml
+++ b/tests/resources/xml/samlp_Query.xml
@@ -1,3 +1,3 @@
-<samlp:Query xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ssp:CustomQueryType">
+<samlp:Query xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" xsi:type="ssp:CustomQueryType">
   <samlp:StatusMessage>urn:some:audience</samlp:StatusMessage>
 </samlp:Query>
diff --git a/tests/resources/xml/samlp_Response.xml b/tests/resources/xml/samlp_Response.xml
index 638a0d1..761dcd7 100644
--- a/tests/resources/xml/samlp_Response.xml
+++ b/tests/resources/xml/samlp_Response.xml
@@ -1,4 +1,4 @@
-<samlp:Response xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ssp="urn:x-simplesamlphp:namespace" MajorVersion="1" MinorVersion="1" IssueInstant="2023-01-24T09:42:26Z" ResponseID="def456">
+<samlp:Response xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ssp="urn:x-simplesamlphp:namespace" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" MajorVersion="1" MinorVersion="1" IssueInstant="2023-01-24T09:42:26Z" ResponseID="def456">
   <samlp:Status>
     <samlp:StatusCode Value="samlp:Responder">
       <samlp:StatusCode Value="samlp:RequestDenied"/>
@@ -30,7 +30,7 @@
         </saml:SubjectConfirmation>
       </saml:Subject>
       <saml:SubjectLocality IPAddress="127.0.0.1" DNSAddress="simplesamlphp.org" />
-      <saml:AuthorityBinding AuthorityKind="samlp:AttributeQuery" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
+      <saml:AuthorityBinding AuthorityKind="samlp:AssertionIdReference" Location="urn:x-simplesamlphp:location" Binding="urn:x-simplesamlphp:binding" />
     </saml:AuthenticationStatement>
   </saml:Assertion>
 </samlp:Response>
diff --git a/tests/src/SAML11/CustomCondition.php b/tests/src/SAML11/CustomCondition.php
index 76f1f40..1a42447 100644
--- a/tests/src/SAML11/CustomCondition.php
+++ b/tests/src/SAML11/CustomCondition.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\saml\AbstractCondition;
 use SimpleSAML\SAML11\XML\saml\Audience;
@@ -61,7 +61,7 @@ public function getAudience(): array
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Condition', InvalidDOMElementException::class);
         Assert::notNull($xml->namespaceURI, InvalidDOMElementException::class);
@@ -84,7 +84,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Condition to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/tests/src/SAML11/CustomQuery.php b/tests/src/SAML11/CustomQuery.php
index e6fb4d1..8cdcab0 100644
--- a/tests/src/SAML11/CustomQuery.php
+++ b/tests/src/SAML11/CustomQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\samlp\AbstractQuery;
 use SimpleSAML\SAML11\XML\samlp\StatusMessage;
@@ -61,7 +61,7 @@ public function getStatusMessage(): array
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Query', InvalidDOMElementException::class);
         Assert::notNull($xml->namespaceURI, InvalidDOMElementException::class);
@@ -84,7 +84,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Query to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/tests/src/SAML11/CustomStatement.php b/tests/src/SAML11/CustomStatement.php
index d54bc5f..6ebf8dd 100644
--- a/tests/src/SAML11/CustomStatement.php
+++ b/tests/src/SAML11/CustomStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\saml\AbstractStatement;
 use SimpleSAML\SAML11\XML\saml\Audience;
@@ -61,7 +61,7 @@ public function getAudience(): array
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'Statement', InvalidDOMElementException::class);
         Assert::notNull($xml->namespaceURI, InvalidDOMElementException::class);
@@ -84,7 +84,7 @@ public static function fromXML(DOMElement $xml): static
     /**
      * Convert this Statement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/tests/src/SAML11/CustomSubjectQuery.php b/tests/src/SAML11/CustomSubjectQuery.php
index 35dfdfe..088d79a 100644
--- a/tests/src/SAML11/CustomSubjectQuery.php
+++ b/tests/src/SAML11/CustomSubjectQuery.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\saml\Subject;
 use SimpleSAML\SAML11\XML\samlp\AbstractSubjectQuery;
@@ -16,7 +16,7 @@
 use SimpleSAML\XMLSchema\Exception\TooManyElementsException;
 use SimpleSAML\XMLSchema\Type\QNameValue;
 
-use function array_pop;
+use function array_last;
 
 /**
  * Example class to demonstrate how SubjectQuery can be extended.
@@ -69,7 +69,7 @@ public function getStatusMessage(): array
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'SubjectQuery', InvalidDOMElementException::class);
         Assert::notNull($xml->namespaceURI, InvalidDOMElementException::class);
@@ -89,14 +89,14 @@ public static function fromXML(DOMElement $xml): static
         Assert::minCount($subject, 1, MissingElementException::class);
         Assert::maxCount($subject, 1, TooManyElementsException::class);
 
-        return new static(array_pop($subject), $statusMessage);
+        return new static(array_last($subject), $statusMessage);
     }
 
 
     /**
      * Convert this SubjectQuery to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/tests/src/SAML11/CustomSubjectStatement.php b/tests/src/SAML11/CustomSubjectStatement.php
index 12b5e50..7fd5ddf 100644
--- a/tests/src/SAML11/CustomSubjectStatement.php
+++ b/tests/src/SAML11/CustomSubjectStatement.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\SAML11\XML\saml\AbstractSubjectStatement;
 use SimpleSAML\SAML11\XML\saml\Audience;
@@ -67,7 +67,7 @@ public function getAudience(): array
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, 'SubjectStatement', InvalidDOMElementException::class);
         Assert::notNull($xml->namespaceURI, InvalidDOMElementException::class);
@@ -87,14 +87,14 @@ public static function fromXML(DOMElement $xml): static
 
         $audience = Audience::getChildrenOfClass($xml);
 
-        return new static(array_pop($subject), $audience);
+        return new static(array_last($subject), $audience);
     }
 
 
     /**
      * Convert this SubjectStatement to XML.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = parent::toXML($parent);
 
diff --git a/tests/src/SAML11/XML/saml/ActionTest.php b/tests/src/SAML11/XML/saml/ActionTest.php
index 7b16e13..e3bd089 100644
--- a/tests/src/SAML11/XML/saml/ActionTest.php
+++ b/tests/src/SAML11/XML/saml/ActionTest.php
@@ -59,9 +59,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:namespace'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($action),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($action);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AdviceTest.php b/tests/src/SAML11/XML/saml/AdviceTest.php
index f3488d8..c280ab3 100644
--- a/tests/src/SAML11/XML/saml/AdviceTest.php
+++ b/tests/src/SAML11/XML/saml/AdviceTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\saml;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -83,23 +83,23 @@ final class AdviceTest extends TestCase
     /** @var \SimpleSAML\XML\Chunk $chunk */
     private static Chunk $chunk;
 
-    /** @var \DOMDocument $conditions */
-    private static DOMDocument $conditions;
+    /** @var \Dom\XMLDocument $conditions */
+    private static Dom\XMLDocument $conditions;
 
-    /** @var \DOMDocument $statement */
-    private static DOMDocument $statement;
+    /** @var \Dom\XMLDocument $statement */
+    private static Dom\XMLDocument $statement;
 
-    /** @var \DOMDocument $subjectStatement */
-    private static DOMDocument $subjectStatement;
+    /** @var \Dom\XMLDocument $subjectStatement */
+    private static Dom\XMLDocument $subjectStatement;
 
-    /** @var \DOMDocument $authnStatement */
-    private static DOMDocument $authnStatement;
+    /** @var \Dom\XMLDocument $authnStatement */
+    private static Dom\XMLDocument $authnStatement;
 
-    /** @var \DOMDocument $authzDecisionStatement */
-//    private static DOMDocument $authzDecisionStatement;
+    /** @var \Dom\XMLDocument $authzDecisionStatement */
+//    private static Dom\XMLDocument $authzDecisionStatement;
 
-    /** @var \DOMDocument $attributeStatement */
-    private static DOMDocument $attributeStatement;
+    /** @var \Dom\XMLDocument $attributeStatement */
+    private static Dom\XMLDocument $attributeStatement;
 
 
     /**
@@ -264,7 +264,7 @@ public function testMarshalling(): void
             SAMLStringValue::fromString('simplesamlphp.org'),
         );
         $authorityBinding = new AuthorityBinding(
-            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AttributeQuery'),
+            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AssertionIdReference'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:location'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:binding'),
         );
@@ -370,10 +370,11 @@ public function testMarshalling(): void
             [self::$chunk],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($advice),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($advice);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/saml/AssertionIDReferenceTest.php b/tests/src/SAML11/XML/saml/AssertionIDReferenceTest.php
index 4e0b6ae..9f29a03 100644
--- a/tests/src/SAML11/XML/saml/AssertionIDReferenceTest.php
+++ b/tests/src/SAML11/XML/saml/AssertionIDReferenceTest.php
@@ -48,9 +48,10 @@ public function testMarshalling(): void
     {
         $assertionIDReference = AssertionIDReference::fromString('_Test');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($assertionIDReference),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($assertionIDReference);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AssertionTest.php b/tests/src/SAML11/XML/saml/AssertionTest.php
index bb0c375..92776c2 100644
--- a/tests/src/SAML11/XML/saml/AssertionTest.php
+++ b/tests/src/SAML11/XML/saml/AssertionTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\saml;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -83,26 +83,26 @@ final class AssertionTest extends TestCase
     /** @var \SimpleSAML\SAML11\Compat\AbstractContainer */
     private static AbstractContainer $containerBackup;
 
-    /** @var \DOMDocument $conditions */
-    private static DOMDocument $conditions;
+    /** @var \Dom\XMLDocument $conditions */
+    private static Dom\XMLDocument $conditions;
 
-    /** @var \DOMDocument $action */
-    //private static DOMDocument $action;
+    /** @var \Dom\XMLDocument $action */
+    //private static Dom\XMLDocument $action;
 
-    /** @var \DOMDocument $statement */
-    private static DOMDocument $statement;
+    /** @var \Dom\XMLDocument $statement */
+    private static Dom\XMLDocument $statement;
 
-    /** @var \DOMDocument $subjectStatement */
-    private static DOMDocument $subjectStatement;
+    /** @var \Dom\XMLDocument $subjectStatement */
+    private static Dom\XMLDocument $subjectStatement;
 
-    /** @var \DOMDocument $authnStatement */
-    private static DOMDocument $authnStatement;
+    /** @var \Dom\XMLDocument $authnStatement */
+    private static Dom\XMLDocument $authnStatement;
 
-    /** @var \DOMDocument $authzDecisionStatement */
-    private static DOMDocument $authzDecisionStatement;
+    /** @var \Dom\XMLDocument $authzDecisionStatement */
+    private static Dom\XMLDocument $authzDecisionStatement;
 
-    /** @var \DOMDocument $attributeStatement */
-    private static DOMDocument $attributeStatement;
+    /** @var \Dom\XMLDocument $attributeStatement */
+    private static Dom\XMLDocument $attributeStatement;
 
 
     /**
@@ -280,10 +280,11 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($assertion),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($assertion);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -409,7 +410,7 @@ private function createAuthenticationStatement(string $id): AuthenticationStatem
         );
 
         $authorityBinding = new AuthorityBinding(
-            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AttributeQuery'),
+            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AssertionIdReference'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:location'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:binding'),
         );
diff --git a/tests/src/SAML11/XML/saml/AttributeDesignatorTest.php b/tests/src/SAML11/XML/saml/AttributeDesignatorTest.php
index f0256a5..c3ad1a2 100644
--- a/tests/src/SAML11/XML/saml/AttributeDesignatorTest.php
+++ b/tests/src/SAML11/XML/saml/AttributeDesignatorTest.php
@@ -58,9 +58,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString('https://example.org/'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($attributeDesignator),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($attributeDesignator);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AttributeStatementTest.php b/tests/src/SAML11/XML/saml/AttributeStatementTest.php
index 320d80f..d57e192 100644
--- a/tests/src/SAML11/XML/saml/AttributeStatementTest.php
+++ b/tests/src/SAML11/XML/saml/AttributeStatementTest.php
@@ -157,10 +157,11 @@ public function testMarshalling(): void
             [$attribute],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($attributeStatement),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($attributeStatement);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/saml/AttributeTest.php b/tests/src/SAML11/XML/saml/AttributeTest.php
index 33de2ef..7b2f90e 100644
--- a/tests/src/SAML11/XML/saml/AttributeTest.php
+++ b/tests/src/SAML11/XML/saml/AttributeTest.php
@@ -78,9 +78,10 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($attribute),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($attribute);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AttributeValueTest.php b/tests/src/SAML11/XML/saml/AttributeValueTest.php
index e2635e2..861dc94 100644
--- a/tests/src/SAML11/XML/saml/AttributeValueTest.php
+++ b/tests/src/SAML11/XML/saml/AttributeValueTest.php
@@ -64,10 +64,11 @@ public function testMarshalling(): void
         $this->assertEquals('2', $av->getValue());
         $this->assertEquals('xs:integer', $av->getXsiType());
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($av),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($av);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -167,12 +168,18 @@ public function testUnmarshallingNameID(): void
 
         $this->assertEquals('abcd-some-value-xyz', $value->getValue());
         $this->assertEquals('urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified', $value->getFormat());
-        $this->assertXmlStringEqualsXmlString($document->saveXML(), $av->toXML()->ownerDocument?->saveXML());
+
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $av->toXML()->ownerDocument;
+        $this->assertXmlStringEqualsXmlString(
+            $document->saveXml($document->documentElement),
+            $ownerDocument->saveXml($ownerDocument->documentElement),
+        );
     }
 
 
     /**
-     * Verifies that we cannot create an AttributeValue that is nullable, like SAML2 allows, but SAML1.1 does not.
+     * Verifies that we cannot create an AttributeValue that is nullable, like SAML 2.0 allows, but SAML1.1 does not.
      *
      * @return void
      */
diff --git a/tests/src/SAML11/XML/saml/AudienceRestrictionConditionTest.php b/tests/src/SAML11/XML/saml/AudienceRestrictionConditionTest.php
index 5f45833..b18c8ca 100644
--- a/tests/src/SAML11/XML/saml/AudienceRestrictionConditionTest.php
+++ b/tests/src/SAML11/XML/saml/AudienceRestrictionConditionTest.php
@@ -56,9 +56,10 @@ public function testMarshalling(): void
         $audience = Audience::fromString('urn:x-simplesamlphp:audience');
         $audienceRestrictionCondition = new AudienceRestrictionCondition([$audience]);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($audienceRestrictionCondition),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($audienceRestrictionCondition);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AudienceTest.php b/tests/src/SAML11/XML/saml/AudienceTest.php
index 01d2c4a..052bd13 100644
--- a/tests/src/SAML11/XML/saml/AudienceTest.php
+++ b/tests/src/SAML11/XML/saml/AudienceTest.php
@@ -52,9 +52,10 @@ public function testMarshalling(): void
     {
         $audience = Audience::fromString('urn:x-simplesamlphp:audience');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($audience),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($audience);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AuthenticationStatementTest.php b/tests/src/SAML11/XML/saml/AuthenticationStatementTest.php
index a1d5224..4a2c737 100644
--- a/tests/src/SAML11/XML/saml/AuthenticationStatementTest.php
+++ b/tests/src/SAML11/XML/saml/AuthenticationStatementTest.php
@@ -148,7 +148,7 @@ public function testMarshalling(): void
         );
 
         $authorityBinding = new AuthorityBinding(
-            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AttributeQuery'),
+            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AssertionIdReference'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:location'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:binding'),
         );
@@ -161,10 +161,11 @@ public function testMarshalling(): void
             [$authorityBinding],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authenticationStatement),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authenticationStatement);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/saml/AuthorityBindingTest.php b/tests/src/SAML11/XML/saml/AuthorityBindingTest.php
index abdbb85..e5bb3c3 100644
--- a/tests/src/SAML11/XML/saml/AuthorityBindingTest.php
+++ b/tests/src/SAML11/XML/saml/AuthorityBindingTest.php
@@ -58,7 +58,7 @@ public function testMarshalling(): void
     {
         $ab = new AuthorityBinding(
             QNameValue::fromParts(
-                NCNameValue::fromString('AttributeQuery'),
+                NCNameValue::fromString('AssertionIdReference'),
                 SAMLAnyURIValue::fromString(C::NS_SAMLP),
                 NCNameValue::fromString('samlp'),
             ),
@@ -66,9 +66,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:binding'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($ab),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($ab);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/AuthorizationDecisionStatementTest.php b/tests/src/SAML11/XML/saml/AuthorizationDecisionStatementTest.php
index 89fcad8..1d3973b 100644
--- a/tests/src/SAML11/XML/saml/AuthorizationDecisionStatementTest.php
+++ b/tests/src/SAML11/XML/saml/AuthorizationDecisionStatementTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\saml;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -47,17 +47,17 @@ final class AuthorizationDecisionStatementTest extends TestCase
     /** @var \SimpleSAML\SAML11\Compat\AbstractContainer */
     private static AbstractContainer $containerBackup;
 
-    /** @var \DOMDocument $action */
-    private static DOMDocument $action;
+    /** @var \Dom\XMLDocument $action */
+    private static Dom\XMLDocument $action;
 
-    /** @var \DOMDocument $advice */
-//    private static DOMDocument $advice;
+    /** @var \Dom\XMLDocument $advice */
+//    private static Dom\XMLDocument $advice;
 
-    /** @var \DOMDocument $evidence */
-    private static DOMDocument $evidence;
+    /** @var \Dom\XMLDocument $evidence */
+    private static Dom\XMLDocument $evidence;
 
-    /** @var \DOMDocument $subject */
-    private static DOMDocument $subject;
+    /** @var \Dom\XMLDocument $subject */
+    private static Dom\XMLDocument $subject;
 
 
     /**
@@ -126,9 +126,10 @@ public function testMarshalling(): void
             $evidence,
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authzDecisionStatement),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authzDecisionStatement);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/ConditionTest.php b/tests/src/SAML11/XML/saml/ConditionTest.php
index d574690..3822880 100644
--- a/tests/src/SAML11/XML/saml/ConditionTest.php
+++ b/tests/src/SAML11/XML/saml/ConditionTest.php
@@ -85,10 +85,11 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($condition),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($condition);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -115,6 +116,8 @@ public function testUnmarshallingUnregistered(): void
         $this->assertEquals('Condition', $chunk->getLocalName());
         $this->assertEquals(C::NS_SAML, $chunk->getNamespaceURI());
 
-        $this->assertEquals($element->ownerDocument?->saveXML($element), strval($condition));
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $element->ownerDocument;
+        $this->assertXmlStringEqualsXmlString($ownerDocument->saveXML($element), strval($condition));
     }
 }
diff --git a/tests/src/SAML11/XML/saml/ConditionsTest.php b/tests/src/SAML11/XML/saml/ConditionsTest.php
index cab7703..9ed4567 100644
--- a/tests/src/SAML11/XML/saml/ConditionsTest.php
+++ b/tests/src/SAML11/XML/saml/ConditionsTest.php
@@ -82,10 +82,11 @@ public function testMarshalling(): void
             SAMLDateTimeValue::fromString('2023-01-24T09:47:26Z'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($conditions),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($conditions);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/saml/ConfirmationMethodTest.php b/tests/src/SAML11/XML/saml/ConfirmationMethodTest.php
index 0c11ed9..683ce4b 100644
--- a/tests/src/SAML11/XML/saml/ConfirmationMethodTest.php
+++ b/tests/src/SAML11/XML/saml/ConfirmationMethodTest.php
@@ -51,9 +51,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString('_Test'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($confirmationMethod),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($confirmationMethod);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/DoNotCacheConditionTest.php b/tests/src/SAML11/XML/saml/DoNotCacheConditionTest.php
index 9372333..4bc548f 100644
--- a/tests/src/SAML11/XML/saml/DoNotCacheConditionTest.php
+++ b/tests/src/SAML11/XML/saml/DoNotCacheConditionTest.php
@@ -52,11 +52,12 @@ public static function setUpBeforeClass(): void
      */
     public function testMarshalling(): void
     {
-        $DoNotCacheCondition = new DoNotCacheCondition();
+        $doNotCacheCondition = new DoNotCacheCondition();
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($DoNotCacheCondition),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($doNotCacheCondition);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/EvidenceTest.php b/tests/src/SAML11/XML/saml/EvidenceTest.php
index 701d4aa..d627525 100644
--- a/tests/src/SAML11/XML/saml/EvidenceTest.php
+++ b/tests/src/SAML11/XML/saml/EvidenceTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\saml;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -80,17 +80,17 @@ final class EvidenceTest extends TestCase
     /** @var \SimpleSAML\SAML11\Compat\AbstractContainer */
     private static AbstractContainer $containerBackup;
 
-    /** @var \DOMDocument $conditions */
-    private static DOMDocument $conditions;
+    /** @var \Dom\Document $conditions */
+    private static Dom\Document $conditions;
 
-    /** @var \DOMDocument $advice */
-    //private static DOMDocument $advice;
+    /** @var \Dom\Document $advice */
+    //private static Dom\Document $advice;
 
-    /** @var \DOMDocument $authzDecisionStatement */
-    //private static DOMDocument $authzDecisionStatement;
+    /** @var \Dom\Document $authzDecisionStatement */
+    //private static Dom\Document $authzDecisionStatement;
 
-    /** @var \DOMDocument $statement */
-    private static DOMDocument $statement;
+    /** @var \Dom\Document $statement */
+    private static Dom\Document $statement;
 
 
     /**
@@ -201,10 +201,11 @@ public function testMarshalling(): void
 
         $evidence = new Evidence([$assertionIDReference], [$assertion]);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($evidence),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($evidence);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -308,7 +309,7 @@ private function createAuthenticationStatement(string $id): AuthenticationStatem
         );
 
         $authorityBinding = new AuthorityBinding(
-            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AttributeQuery'),
+            QNameValue::fromString('{' . C::NS_SAMLP . '}samlp:AssertionIdReference'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:location'),
             SAMLAnyURIValue::fromString('urn:x-simplesamlphp:binding'),
         );
diff --git a/tests/src/SAML11/XML/saml/NameIdentifierTest.php b/tests/src/SAML11/XML/saml/NameIdentifierTest.php
index 47d4f54..de50cd6 100644
--- a/tests/src/SAML11/XML/saml/NameIdentifierTest.php
+++ b/tests/src/SAML11/XML/saml/NameIdentifierTest.php
@@ -59,9 +59,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString('urn:the:format'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($nameIdentifier),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($nameIdentifier);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/StatementTest.php b/tests/src/SAML11/XML/saml/StatementTest.php
index 41676a5..1278239 100644
--- a/tests/src/SAML11/XML/saml/StatementTest.php
+++ b/tests/src/SAML11/XML/saml/StatementTest.php
@@ -85,7 +85,7 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
+        $this->assertXmlStringEqualsXmlString(
             self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
             strval($statement),
         );
@@ -107,10 +107,11 @@ public function testUnmarshalling(): void
         $this->assertCount(1, $audience);
         $this->assertEquals('urn:some:audience', $audience[0]->getContent());
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($statement),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($statement);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -134,6 +135,8 @@ public function testUnmarshallingUnregistered(): void
         $this->assertEquals('Statement', $chunk->getLocalName());
         $this->assertEquals(C::NS_SAML, $chunk->getNamespaceURI());
 
-        $this->assertEquals($element->ownerDocument?->saveXML($element), strval($statement));
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $element->ownerDocument;
+        $this->assertXmlStringEqualsXmlString($ownerDocument->saveXML($element), strval($statement));
     }
 }
diff --git a/tests/src/SAML11/XML/saml/SubjectConfirmationDataTest.php b/tests/src/SAML11/XML/saml/SubjectConfirmationDataTest.php
index 85c1044..b82e4a7 100644
--- a/tests/src/SAML11/XML/saml/SubjectConfirmationDataTest.php
+++ b/tests/src/SAML11/XML/saml/SubjectConfirmationDataTest.php
@@ -63,10 +63,11 @@ public function testMarshalling(): void
         $this->assertEquals('2', strval($scd->getValue()));
         $this->assertEquals('xs:integer', $scd->getXsiType());
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($scd),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($scd);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -93,9 +94,10 @@ public function testMarshallingNull(): void
         $this->assertNull($scd->getValue());
         $this->assertEquals('xs:nil', $scd->getXsiType());
         $nssaml = C::NS_SAML;
+        $nsxs = C_XSI::NS_XS;
         $nsxsi = C_XSI::NS_XSI;
         $xml = <<<XML
-<saml:SubjectConfirmationData xmlns:saml="{$nssaml}" xmlns:xsi="{$nsxsi}" xsi:nil="1"/>
+<saml:SubjectConfirmationData xmlns:saml="{$nssaml}" xmlns:xs="{$nsxs}" xmlns:xsi="{$nsxsi}" xsi:nil="1"/>
 XML;
         $this->assertEquals(
             $xml,
@@ -125,6 +127,12 @@ public function testUnmarshallingNameID(): void
 
         $this->assertEquals('abcd-some-value-xyz', $value->getValue());
         $this->assertEquals('urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified', $value->getFormat());
-        $this->assertXmlStringEqualsXmlString($document->saveXML(), $scd->toXML()->ownerDocument?->saveXML());
+
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $scd->toXML()->ownerDocument;
+        $this->assertXmlStringEqualsXmlString(
+            $document->saveXML($document->documentElement),
+            $ownerDocument->saveXML($ownerDocument->documentElement),
+        );
     }
 }
diff --git a/tests/src/SAML11/XML/saml/SubjectConfirmationTest.php b/tests/src/SAML11/XML/saml/SubjectConfirmationTest.php
index c5b9df5..a0b7128 100644
--- a/tests/src/SAML11/XML/saml/SubjectConfirmationTest.php
+++ b/tests/src/SAML11/XML/saml/SubjectConfirmationTest.php
@@ -123,9 +123,10 @@ public function testMarshalling(): void
             $keyInfo,
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($sc),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($sc);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/saml/SubjectLocalityTest.php b/tests/src/SAML11/XML/saml/SubjectLocalityTest.php
index dbbf602..552f09e 100644
--- a/tests/src/SAML11/XML/saml/SubjectLocalityTest.php
+++ b/tests/src/SAML11/XML/saml/SubjectLocalityTest.php
@@ -58,10 +58,11 @@ public function testMarshalling(): void
             SAMLStringValue::fromString('simplesamlphp.org'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($sl),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($sl);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/saml/SubjectStatementTest.php b/tests/src/SAML11/XML/saml/SubjectStatementTest.php
index 474d6f5..7d6e70e 100644
--- a/tests/src/SAML11/XML/saml/SubjectStatementTest.php
+++ b/tests/src/SAML11/XML/saml/SubjectStatementTest.php
@@ -162,7 +162,7 @@ public function testMarshalling(): void
         $audience = Audience::fromString('urn:x-simplesamlphp:audience');
         $subjectStatement = new CustomSubjectStatement($subject, [$audience]);
 
-        $this->assertEquals(
+        $this->assertXmlStringEqualsXmlString(
             self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
             strval($subjectStatement),
         );
@@ -181,10 +181,11 @@ public function testUnmarshalling(): void
         $this->assertCount(1, $audience);
         $this->assertEquals('urn:x-simplesamlphp:audience', $audience[0]->getContent());
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($subjectStatement),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($subjectStatement);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -208,6 +209,8 @@ public function testUnmarshallingUnregistered(): void
         $this->assertEquals('SubjectStatement', $chunk->getLocalName());
         $this->assertEquals(C::NS_SAML, $chunk->getNamespaceURI());
 
-        $this->assertEquals($element->ownerDocument?->saveXML($element), strval($subjectStatement));
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $element->ownerDocument;
+        $this->assertXmlStringEqualsXmlString($ownerDocument->saveXML($element), strval($subjectStatement));
     }
 }
diff --git a/tests/src/SAML11/XML/saml/SubjectTest.php b/tests/src/SAML11/XML/saml/SubjectTest.php
index 18856c5..fb938d4 100644
--- a/tests/src/SAML11/XML/saml/SubjectTest.php
+++ b/tests/src/SAML11/XML/saml/SubjectTest.php
@@ -135,9 +135,10 @@ public function testMarshalling(): void
 
         $subject = new Subject($sc, $nameIdentifier);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($subject),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($subject);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/AssertionArtifactTest.php b/tests/src/SAML11/XML/samlp/AssertionArtifactTest.php
index cd4795a..df02134 100644
--- a/tests/src/SAML11/XML/samlp/AssertionArtifactTest.php
+++ b/tests/src/SAML11/XML/samlp/AssertionArtifactTest.php
@@ -52,9 +52,10 @@ public function testMarshalling(): void
     {
         $assertionArtifact = AssertionArtifact::fromString('AAEbuqrPjR1XORIHk5YAV8I4sM0nKP2CLV+h1CMiWbnkaWvvlJ0g4Ess');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($assertionArtifact),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($assertionArtifact);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/AttributeQueryTest.php b/tests/src/SAML11/XML/samlp/AttributeQueryTest.php
index b601756..88a7d5a 100644
--- a/tests/src/SAML11/XML/samlp/AttributeQueryTest.php
+++ b/tests/src/SAML11/XML/samlp/AttributeQueryTest.php
@@ -154,9 +154,10 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($attributeQuery),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($attributeQuery);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/AuthenticationQueryTest.php b/tests/src/SAML11/XML/samlp/AuthenticationQueryTest.php
index 0191d74..715f5ca 100644
--- a/tests/src/SAML11/XML/samlp/AuthenticationQueryTest.php
+++ b/tests/src/SAML11/XML/samlp/AuthenticationQueryTest.php
@@ -144,9 +144,10 @@ public function testMarshalling(): void
             SAMLAnyURIValue::fromString(C::AC_PASSWORD),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authnQuery),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authnQuery);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/AuthorizationDecisionQueryTest.php b/tests/src/SAML11/XML/samlp/AuthorizationDecisionQueryTest.php
index 09dfa0a..ba99973 100644
--- a/tests/src/SAML11/XML/samlp/AuthorizationDecisionQueryTest.php
+++ b/tests/src/SAML11/XML/samlp/AuthorizationDecisionQueryTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\samlp;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -70,23 +70,23 @@ final class AuthorizationDecisionQueryTest extends TestCase
     /** @var string[] */
     private static array $certData;
 
-    /** @var \DOMDocument $advice */
-    //private static DOMDocument $advice;
+    /** @var \Dom\XMLDocument $advice */
+    //private static Dom\XMLDocument $advice;
 
-    /** @var \DOMDocument $statement */
-    //private static DOMDocument $statement;
+    /** @var \Dom\XMLDocument $statement */
+    //private static Dom\XMLDocument $statement;
 
-    /** @var \DOMDocument $subjectStatement */
-    //private static DOMDocument $subjectStatement;
+    /** @var \Dom\XMLDocument $subjectStatement */
+    //private static Dom\XMLDocument $subjectStatement;
 
-    /** @var \DOMDocument $authnStatement */
-    private static DOMDocument $authnStatement;
+    /** @var \Dom\XMLDocument $authnStatement */
+    private static Dom\XMLDocument $authnStatement;
 
-    /** @var \DOMDocument $authzDecisionStatement */
-    //private static DOMDocument $authzDecisionStatement;
+    /** @var \Dom\XMLDocument $authzDecisionStatement */
+    //private static \Dom\XMLDocument $authzDecisionStatement;
 
-    /** @var \DOMDocument $attributeStatement */
-    private static DOMDocument $attributeStatement;
+    /** @var \Dom\XMLDocument $attributeStatement */
+    private static Dom\XMLDocument $attributeStatement;
 
 
     /**
@@ -237,9 +237,10 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authorizationDecisionQuery),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authorizationDecisionQuery);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/QueryTest.php b/tests/src/SAML11/XML/samlp/QueryTest.php
index a9bbc97..c9119fe 100644
--- a/tests/src/SAML11/XML/samlp/QueryTest.php
+++ b/tests/src/SAML11/XML/samlp/QueryTest.php
@@ -85,10 +85,11 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($query),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($query);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -115,6 +116,9 @@ public function testUnmarshallingUnregistered(): void
         $this->assertEquals('Query', $chunk->getLocalName());
         $this->assertEquals(C::NS_SAMLP, $chunk->getNamespaceURI());
 
-        $this->assertEquals($element->ownerDocument?->saveXML($element), strval($query));
+        /** @var \Dom\XMLDocument $ownerDocument */
+        $ownerDocument = $element->ownerDocument;
+
+        $this->assertXmlStringEqualsXmlString($ownerDocument->saveXml($element), strval($query));
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/RespondWithTest.php b/tests/src/SAML11/XML/samlp/RespondWithTest.php
index 06b2e8f..52b8a23 100644
--- a/tests/src/SAML11/XML/samlp/RespondWithTest.php
+++ b/tests/src/SAML11/XML/samlp/RespondWithTest.php
@@ -55,9 +55,10 @@ public function testMarshalling(): void
             ),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($respondWith),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($respondWith);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/ResponseTest.php b/tests/src/SAML11/XML/samlp/ResponseTest.php
index 86e4983..fd2a0c8 100644
--- a/tests/src/SAML11/XML/samlp/ResponseTest.php
+++ b/tests/src/SAML11/XML/samlp/ResponseTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\samlp;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -50,8 +50,8 @@ final class ResponseTest extends TestCase
     use SerializableElementTestTrait;
 
 
-    /** @var \DOMDocument $authnStatement */
-    private static DOMDocument $authnStatement;
+    /** @var \Dom\XMLDocument $authnStatement */
+    private static Dom\XMLDocument $authnStatement;
 
 
     /**
@@ -125,9 +125,10 @@ public function testMarshalling(): void
             [$assertion],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($response),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($response);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/StatusCodeTest.php b/tests/src/SAML11/XML/samlp/StatusCodeTest.php
index 5e82d3d..0512d03 100644
--- a/tests/src/SAML11/XML/samlp/StatusCodeTest.php
+++ b/tests/src/SAML11/XML/samlp/StatusCodeTest.php
@@ -58,9 +58,10 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($statusCode),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($statusCode);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/StatusDetailTest.php b/tests/src/SAML11/XML/samlp/StatusDetailTest.php
index 1ea228d..9cc2ae0 100644
--- a/tests/src/SAML11/XML/samlp/StatusDetailTest.php
+++ b/tests/src/SAML11/XML/samlp/StatusDetailTest.php
@@ -56,10 +56,11 @@ public function testMarshalling(): void
 
         $statusDetail = new StatusDetail([new Chunk($document->documentElement)]);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($statusDetail),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($statusDetail);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
diff --git a/tests/src/SAML11/XML/samlp/StatusMessageTest.php b/tests/src/SAML11/XML/samlp/StatusMessageTest.php
index 0e493fa..1c33be8 100644
--- a/tests/src/SAML11/XML/samlp/StatusMessageTest.php
+++ b/tests/src/SAML11/XML/samlp/StatusMessageTest.php
@@ -48,9 +48,10 @@ public function testMarshalling(): void
     {
         $statusMessage = StatusMessage::fromString('Something went wrong');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($statusMessage),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($statusMessage);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/src/SAML11/XML/samlp/StatusTest.php b/tests/src/SAML11/XML/samlp/StatusTest.php
index 9396637..58a04b6 100644
--- a/tests/src/SAML11/XML/samlp/StatusTest.php
+++ b/tests/src/SAML11/XML/samlp/StatusTest.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\Test\SAML11\XML\samlp;
 
-use DOMDocument;
+use Dom;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
@@ -38,8 +38,8 @@ final class StatusTest extends TestCase
     use SerializableElementTestTrait;
 
 
-    /** @var \DOMDocument $detail */
-    private static DOMDocument $detail;
+    /** @var \Dom\XMLDocument $detail */
+    private static Dom\XMLDocument $detail;
 
 
     /**
@@ -79,10 +79,11 @@ public function testMarshalling(): void
             ),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($status),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($status);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -111,7 +112,7 @@ public function testMarshallingElementOrdering(): void
         $this->assertCount(1, $statusElements);
 
         // Test ordering of Status contents
-        /** @var \DOMElement[] $statusElements */
+        /** @var \Dom\Element[] $statusElements */
         $statusElements = XPath::xpQuery($statusElement, './saml_protocol:StatusCode/following-sibling::*', $xpCache);
         $this->assertCount(2, $statusElements);
         $this->assertEquals('samlp:StatusMessage', $statusElements[0]->tagName);
diff --git a/tests/src/SAML11/XML/samlp/SubjectQueryTest.php b/tests/src/SAML11/XML/samlp/SubjectQueryTest.php
index 1fa9e0a..3a7dc0d 100644
--- a/tests/src/SAML11/XML/samlp/SubjectQueryTest.php
+++ b/tests/src/SAML11/XML/samlp/SubjectQueryTest.php
@@ -167,10 +167,11 @@ public function testMarshalling(): void
             ],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($subjectQuery),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($subjectQuery);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -187,7 +188,7 @@ public function testUnmarshallingUnregistered(): void
 
         // Normalize the DOMElement by importing it into a clean empty document
         $newDoc = DOMDocumentFactory::create();
-        /** @var \DOMElement $element */
+        /** @var \Dom\Element $element */
         $element = $newDoc->appendChild($newDoc->importNode($element, true));
 
         $subjectQuery = AbstractSubjectQuery::fromXML($element);