diff --git a/composer.lock b/composer.lock
index 814ca6a..bc91cf8 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1440,16 +1440,16 @@
         },
         {
             "name": "symfony/console",
-            "version": "v5.3.10",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/console.git",
-                "reference": "d4e409d9fbcfbf71af0e5a940abb7b0b4bad0bd3"
+                "reference": "3e7ab8f5905058984899b05a4648096f558bfeba"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/console/zipball/d4e409d9fbcfbf71af0e5a940abb7b0b4bad0bd3",
-                "reference": "d4e409d9fbcfbf71af0e5a940abb7b0b4bad0bd3",
+                "url": "https://api.github.com/repos/symfony/console/zipball/3e7ab8f5905058984899b05a4648096f558bfeba",
+                "reference": "3e7ab8f5905058984899b05a4648096f558bfeba",
                 "shasum": ""
             },
             "require": {
@@ -1462,7 +1462,6 @@
                 "symfony/string": "^5.1"
             },
             "conflict": {
-                "psr/log": ">=3",
                 "symfony/dependency-injection": "<4.4",
                 "symfony/dotenv": "<5.1",
                 "symfony/event-dispatcher": "<4.4",
@@ -1519,7 +1518,7 @@
                 "terminal"
             ],
             "support": {
-                "source": "https://github.com/symfony/console/tree/v5.3.10"
+                "source": "https://github.com/symfony/console/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1535,20 +1534,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-10-26T09:30:15+00:00"
+            "time": "2021-11-21T19:41:05+00:00"
         },
         {
             "name": "symfony/deprecation-contracts",
-            "version": "v2.4.0",
+            "version": "v2.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/deprecation-contracts.git",
-                "reference": "5f38c8804a9e97d23e0c8d63341088cd8a22d627"
+                "reference": "6f981ee24cf69ee7ce9736146d1c57c2780598a8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/deprecation-contracts/zipball/5f38c8804a9e97d23e0c8d63341088cd8a22d627",
-                "reference": "5f38c8804a9e97d23e0c8d63341088cd8a22d627",
+                "url": "https://api.github.com/repos/symfony/deprecation-contracts/zipball/6f981ee24cf69ee7ce9736146d1c57c2780598a8",
+                "reference": "6f981ee24cf69ee7ce9736146d1c57c2780598a8",
                 "shasum": ""
             },
             "require": {
@@ -1557,7 +1556,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "2.4-dev"
+                    "dev-main": "2.5-dev"
                 },
                 "thanks": {
                     "name": "symfony/contracts",
@@ -1586,7 +1585,7 @@
             "description": "A generic function and convention to trigger deprecation notices",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/deprecation-contracts/tree/v2.4.0"
+                "source": "https://github.com/symfony/deprecation-contracts/tree/v2.5.0"
             },
             "funding": [
                 {
@@ -1602,20 +1601,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-03-23T23:28:01+00:00"
+            "time": "2021-07-12T14:48:14+00:00"
         },
         {
             "name": "symfony/http-foundation",
-            "version": "v5.3.10",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/http-foundation.git",
-                "reference": "9f34f02e8a5fdc7a56bafe011cea1ce97300e54c"
+                "reference": "d1e7059ebeb0b8f9fe5eb5b26eacd2e3c1f371cc"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/http-foundation/zipball/9f34f02e8a5fdc7a56bafe011cea1ce97300e54c",
-                "reference": "9f34f02e8a5fdc7a56bafe011cea1ce97300e54c",
+                "url": "https://api.github.com/repos/symfony/http-foundation/zipball/d1e7059ebeb0b8f9fe5eb5b26eacd2e3c1f371cc",
+                "reference": "d1e7059ebeb0b8f9fe5eb5b26eacd2e3c1f371cc",
                 "shasum": ""
             },
             "require": {
@@ -1659,7 +1658,7 @@
             "description": "Defines an object-oriented layer for the HTTP specification",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/http-foundation/tree/v5.3.10"
+                "source": "https://github.com/symfony/http-foundation/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1675,20 +1674,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-10-11T15:41:55+00:00"
+            "time": "2021-11-04T16:37:19+00:00"
         },
         {
             "name": "symfony/mime",
-            "version": "v5.3.8",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/mime.git",
-                "reference": "a756033d0a7e53db389618653ae991eba5a19a11"
+                "reference": "dffc0684f10526db12c52fcd6238c64695426d61"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/mime/zipball/a756033d0a7e53db389618653ae991eba5a19a11",
-                "reference": "a756033d0a7e53db389618653ae991eba5a19a11",
+                "url": "https://api.github.com/repos/symfony/mime/zipball/dffc0684f10526db12c52fcd6238c64695426d61",
+                "reference": "dffc0684f10526db12c52fcd6238c64695426d61",
                 "shasum": ""
             },
             "require": {
@@ -1742,7 +1741,7 @@
                 "mime-type"
             ],
             "support": {
-                "source": "https://github.com/symfony/mime/tree/v5.3.8"
+                "source": "https://github.com/symfony/mime/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1758,7 +1757,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-09-10T12:30:38+00:00"
+            "time": "2021-11-20T16:42:42+00:00"
         },
         {
             "name": "symfony/polyfill-ctype",
@@ -2415,16 +2414,16 @@
         },
         {
             "name": "symfony/process",
-            "version": "v5.3.7",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/process.git",
-                "reference": "38f26c7d6ed535217ea393e05634cb0b244a1967"
+                "reference": "6c99204de85d04ca17f16c466fc61896960b0636"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/process/zipball/38f26c7d6ed535217ea393e05634cb0b244a1967",
-                "reference": "38f26c7d6ed535217ea393e05634cb0b244a1967",
+                "url": "https://api.github.com/repos/symfony/process/zipball/6c99204de85d04ca17f16c466fc61896960b0636",
+                "reference": "6c99204de85d04ca17f16c466fc61896960b0636",
                 "shasum": ""
             },
             "require": {
@@ -2457,7 +2456,7 @@
             "description": "Executes commands in sub-processes",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/process/tree/v5.3.7"
+                "source": "https://github.com/symfony/process/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -2473,25 +2472,29 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-08-04T21:20:46+00:00"
+            "time": "2021-11-17T12:16:12+00:00"
         },
         {
             "name": "symfony/service-contracts",
-            "version": "v2.4.0",
+            "version": "v2.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/service-contracts.git",
-                "reference": "f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb"
+                "reference": "1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/service-contracts/zipball/f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb",
-                "reference": "f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb",
+                "url": "https://api.github.com/repos/symfony/service-contracts/zipball/1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc",
+                "reference": "1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc",
                 "shasum": ""
             },
             "require": {
                 "php": ">=7.2.5",
-                "psr/container": "^1.1"
+                "psr/container": "^1.1",
+                "symfony/deprecation-contracts": "^2.1"
+            },
+            "conflict": {
+                "ext-psr": "<1.1|>=2"
             },
             "suggest": {
                 "symfony/service-implementation": ""
@@ -2499,7 +2502,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "2.4-dev"
+                    "dev-main": "2.5-dev"
                 },
                 "thanks": {
                     "name": "symfony/contracts",
@@ -2536,7 +2539,7 @@
                 "standards"
             ],
             "support": {
-                "source": "https://github.com/symfony/service-contracts/tree/v2.4.0"
+                "source": "https://github.com/symfony/service-contracts/tree/v2.5.0"
             },
             "funding": [
                 {
@@ -2552,7 +2555,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-04-01T10:43:52+00:00"
+            "time": "2021-11-04T16:48:04+00:00"
         },
         {
             "name": "symfony/string",
@@ -2639,16 +2642,16 @@
         },
         {
             "name": "symfony/yaml",
-            "version": "v5.3.6",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
-                "reference": "4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7"
+                "reference": "226638aa877bc4104e619a15f27d8141cd6b4e4a"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/yaml/zipball/4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7",
-                "reference": "4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/226638aa877bc4104e619a15f27d8141cd6b4e4a",
+                "reference": "226638aa877bc4104e619a15f27d8141cd6b4e4a",
                 "shasum": ""
             },
             "require": {
@@ -2694,7 +2697,7 @@
             "description": "Loads and dumps YAML files",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/yaml/tree/v5.3.6"
+                "source": "https://github.com/symfony/yaml/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -2710,7 +2713,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-07-29T06:20:01+00:00"
+            "time": "2021-11-20T16:42:42+00:00"
         },
         {
             "name": "webuni/front-matter",
diff --git a/lib/DOMTokenList.php b/lib/DOMTokenList.php
new file mode 100644
index 0000000..f644fc1
--- /dev/null
+++ b/lib/DOMTokenList.php
@@ -0,0 +1,331 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+use MensBeam\Framework\MagicProperties,
+    MensBeam\HTML\DOM\Inner\Reflection;
+
+
+class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
+    use MagicProperties;
+
+
+    protected string $localName;
+    protected \WeakReference $element;
+
+    protected int $_length = 0;
+    protected int $position = 0;
+    # A DOMTokenList object has an associated token set (a set), which is initially
+    # empty.
+    protected array $tokenSet = [];
+
+    private const ASCII_WHITESPACE_REGEX = '/[\t\n\x0c\r ]+/';
+
+
+    protected function __get_length(): int {
+        return $this->_length;
+    }
+
+    protected function __get_value(): string {
+        # The value attribute must return the result of running this’s serialize steps.
+        return $this->__toString();
+    }
+
+    protected function __set_value(string $value) {
+        # Setting the value attribute must set an attribute value for the associated
+        # element using associated attribute’s local name and the given value.
+        $element = Reflection::getProtectedProperty($this->element->get(), 'innerNode');
+        $element->setAttribute($this->localName, $value);
+        // Also update the token set and the length.
+        $this->tokenSet = $this->parseOrderedSet($value);
+        $this->_length = count($this->tokenSet);
+    }
+
+
+    protected function __construct(Element $element, string $attributeLocalName) {
+        # A DOMTokenList object also has an associated element and an attribute’s local
+        # name.
+
+        # When a DOMTokenList object is created, then:
+        #
+        # 1. Let element be associated element.
+        // Using a weak reference here to prevent a circular reference. We should be
+        // creating a weak reference to the inner element, but there are memory
+        // management issues concerning PHP's garbage reference counting.
+        $this->element = \WeakReference::create($element);
+        # 2. Let localName be associated attribute’s local name.
+        $this->localName = $attributeLocalName;
+        # 3. Let value be the result of getting an attribute value given element and
+        # localName.
+        $element = Reflection::getProtectedProperty($element, 'innerNode');
+        $value = $element->getAttribute($attributeLocalName);
+        # 4. Run the attribute change steps for element, localName, value, value, and
+        # null.
+        $this->attributeChange($attributeLocalName, $value, $value);
+    }
+
+
+    public function add(...$tokens): void {
+        # 1. For each token in tokens:
+        foreach ($tokens as $token) {
+            # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
+            if ($token === '') {
+                throw new DOMException(DOMException::SYNTAX_ERROR);
+            }
+
+            # 2. If token contains any ASCII whitespace, then throw an
+            # "InvalidCharacterError" DOMException.
+            if (preg_match(self::ASCII_WHITESPACE_REGEX, $token)) {
+                throw new DOMException(DOMException::INVALID_CHARACTER);
+            }
+        }
+
+        # 2. For each token in tokens, append token to this’s token set.
+        foreach ($tokens as $token) {
+            if (!in_array($token, $this->tokenSet)) {
+                $this->tokenSet[] = $token;
+                $this->_length++;
+            }
+        }
+
+        # 3. Run the update steps.
+        $this->update();
+    }
+
+    public function contains(string $token): bool {
+        return (in_array($token, $this->tokenSet));
+    }
+
+    public function count(): int {
+        return $this->_length;
+    }
+
+    public function current(): ?string {
+        return $this->item($this->position);
+    }
+
+    public function item(int $index): ?string {
+        # The item(index) method steps are:
+        # 1. If index is equal to or greater than this’s token set’s size, then return null.
+        if ($index >= $this->_length) {
+            return null;
+        }
+        # 2. Return this’s token set[index].
+        return $this->tokenSet[$index];
+    }
+
+    public function key(): int {
+        return $this->position;
+    }
+
+    public function next(): void {
+        ++$this->position;
+    }
+
+    public function rewind(): void {
+        $this->position = 0;
+    }
+
+    public function offsetExists($offset): bool {
+        return isset($this->tokenSet[$offset]);
+    }
+
+    public function offsetGet($offset): string {
+        return $this->item($offset);
+    }
+
+    public function offsetSet($offset, $value): void {
+        // Spec says nothing about setting values on DOMTokenList outside of add();
+        // browsers silently fail here.
+    }
+
+    public function offsetUnset($offset): void {
+        // Spec says nothing about unsetting values on DOMTokenList outside of remove();
+        // browsers silently fail here.
+    }
+
+    public function remove(...$tokens): void {
+        # 1. For each token in tokens:
+        foreach ($tokens as $token) {
+            # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
+            if ($token === '') {
+                throw new DOMException(DOMException::SYNTAX_ERROR);
+            }
+
+            # 2. If token contains any ASCII whitespace, then throw an
+            # "InvalidCharacterError" DOMException.
+            if (preg_match(self::ASCII_WHITESPACE_REGEX, $token)) {
+                throw new DOMException(DOMException::INVALID_CHARACTER);
+            }
+        }
+
+        # For each token in tokens, remove token from this’s token set.
+        $changed = false;
+        foreach ($tokens as $token) {
+            if ($key = array_search($token, $this->tokenSet, true)) {
+                unset($this->tokenSet[$key]);
+                $this->_length--;
+                $changed = true;
+            }
+        }
+
+        if ($changed) {
+            $this->tokenSet = array_values($this->tokenSet);
+        }
+
+        # 3. Run the update steps.
+        $this->update();
+    }
+
+    public function replace(string $token, string $newToken): bool {
+        # 1. If either token or newToken is the empty string, then throw a "SyntaxError"
+        # DOMException.
+        if ($token === '' || $newToken === '') {
+            throw new DOMException(DOMException::SYNTAX_ERROR);
+        }
+
+        # 2. If either token or newToken contains any ASCII whitespace, then throw an
+        # "InvalidCharacterError" DOMException.
+        if (preg_match(self::ASCII_WHITESPACE_REGEX, $token) || preg_match(self::ASCII_WHITESPACE_REGEX, $newToken)) {
+            throw new DOMException(DOMException::INVALID_CHARACTER);
+        }
+
+        # 3. If this’s token set does not contain token, then return false.
+        if (!($key = array_search($token, $this->tokenSet))) {
+            return false;
+        }
+
+        # 4. Replace token in this’s token set with newToken.
+        $this->tokenSet[$key] = $newToken;
+
+        # 5. Run the update steps.
+        $this->update();
+
+        # 6. Return true.
+        return true;
+    }
+
+    public function supports(string $token): bool {
+        # 1. Let result be the return value of validation steps called with token.
+        # 2. Return result.
+        #
+        # A DOMTokenList object’s validation steps for a given token are:
+        #
+        # 1. If the associated attribute’s local name does not define supported tokens,
+        # throw a TypeError.
+        # 2. Let lowercase token be a copy of token, in ASCII lowercase.
+        # 3. If lowercase token is present in supported tokens, return true.
+        # 4. Return false.
+
+        // This class is presently only used for Element::classList, and it supports any
+        // valid class name as a token. So, there's nothing to do here at the moment.
+        // Just return true.
+        return true;
+    }
+
+    public function toggle(string $token, ?bool $force = null): bool {
+        # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
+        if ($token === '') {
+            throw new DOMException(DOMException::SYNTAX_ERROR);
+        }
+
+        # 2. If token contains any ASCII whitespace, then throw an
+        # "InvalidCharacterError" DOMException.
+        if (preg_match(self::ASCII_WHITESPACE_REGEX, $token)) {
+            throw new DOMException(DOMException::INVALID_CHARACTER);
+        }
+
+        # 3. If this’s token set[token] exists, then:
+        if (in_array($token, $this->tokenSet)) {
+            # 1. If force is either not given or is false, then remove token from this’s
+            # token set, run the update steps and return false.
+            if (!$force) {
+                $this->remove($token);
+                return false;
+            }
+
+            # 2. Return true.
+            return true;
+        }
+        # 4. Otherwise, if force not given or is true, append token to this’s token set,
+        # run the update steps, and return true.
+        elseif ($force === null || $force === true) {
+            $this->add($token);
+            return true;
+        }
+
+        # 5. Return false.
+        return false;
+    }
+
+    public function valid(): bool {
+        return array_key_exists($this->position, $this->tokenSet);
+    }
+
+
+    protected function attributeChange(string $localName, ?string $oldValue = null, ?string $value = null, ?string $namespace = null): void {
+        # A DOMTokenList object has these attribute change steps for its associated
+        # element:
+        #
+        # 1. If localName is associated attribute’s local name, namespace is null, and
+        # value is null, then empty token set.
+        if ($localName === $this->localName && $namespace === null && $value === null) {
+            $this->tokenSet = [];
+            $this->_length = 0;
+        }
+        # 2. Otherwise, if localName is associated attribute’s local name, namespace is
+        # null, then set token set to value, parsed.
+        elseif ($localName === $this->localName && $namespace === null) {
+            $this->tokenSet = $this->parseOrderedSet($value);
+            $this->_length = count($this->tokenSet);
+        }
+    }
+
+    protected function parseOrderedSet(string $input): array {
+        if ($input === '') {
+            return [];
+        }
+
+        # The ordered set parser takes a string input and then runs these steps:
+        #
+        # 1. Let inputTokens be the result of splitting input on ASCII whitespace.
+        // There isn't a Set object in php, so make sure all the tokens are unique.
+        $inputTokens = array_unique(preg_split(self::ASCII_WHITESPACE_REGEX, $input));
+
+        # 2. Let tokens be a new ordered set.
+        # 3. For each token in inputTokens, append token to tokens.
+        # 4. Return tokens.
+        // There isn't a Set object in php, so just return the uniqued input tokens.
+        return $inputTokens;
+    }
+
+    protected function update(): void {
+        # A DOMTokenList object’s update steps are:
+        #
+        # 1. If the associated element does not have an associated attribute and token
+        # set is empty, then return.
+        $element = Reflection::getProtectedProperty($this->element->get(), 'innerNode');
+        if (!$element->hasAttribute('class') && count($this->tokenSet) === 0) {
+            return;
+        }
+
+        # 2. Set an attribute value for the associated element using associated
+        # attribute’s local name and the result of running the ordered set serializer
+        # for token set.
+        $class = $element->ownerDocument->createAttribute($this->localName);
+        $class->value = $this->__toString();
+        $element->setAttributeNode($class);
+    }
+
+
+    public function __toString(): string {
+        # The ordered set serializer takes a set and returns the concatenation of set
+        # using U+0020 SPACE.
+        return implode(' ', $this->tokenSet);
+    }
+}
diff --git a/lib/Element.php b/lib/Element.php
index 75272ee..3a0348b 100644
--- a/lib/Element.php
+++ b/lib/Element.php
@@ -22,6 +22,15 @@ class Element extends Node {
         return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\NamedNodeMap', $this, ($this instanceof Document) ? $this->innerNode : $this->innerNode->ownerDocument, $this->innerNode->attributes);
     }
 
+    protected function __get_classList(): DOMTokenList {
+        # The classList getter steps are to return a DOMTokenList object whose
+        # associated element is this and whose associated attribute’s local name is
+        # class. The token set of this particular DOMTokenList object are also known as
+        # the element’s classes.
+        // DOMTokenLists cannot be created from their constructors normally.
+        return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\DOMTokenList', $this, 'class');
+    }
+
     protected function __get_className(): string {
         # The className attribute must reflect the "class" content attribute.
         # Return the result of running get an attribute value given this and name.
@@ -339,39 +348,6 @@ class Element extends Node {
             $this->innerNode->setAttributeNS($namespace, $qualifiedName, $value);
         }
 
-        /*# 2. Set an attribute value for this using localName, value, and also prefix and
-        #    namespace.
-        // Going to try to handle this by getting the PHP DOM to do the heavy lifting
-        // when we can because it's faster.
-        // NOTE: We create attribute nodes so that xmlns attributes don't get lost;
-        // otherwise they cannot be serialized
-        if ($namespace === self::XMLNS_NAMESPACE) {
-            // Xmlns attributes have special bugs just for them. How lucky! Xmlns attribute
-            // nodes won't stick and can actually cause segmentation faults if created on a
-            // no longer existing document element, appended to another element, and then
-            // retrieved. So, use the methods used in Document::createAttributeNS to get an
-            // attribute node.
-            $a = $this->ownerDocument->createAttributeNS($namespace, $qualifiedName);
-
-            $a->value = $this->escapeString($value, true);
-            $this->setAttributeNodeNS($a);
-        } else {
-            try {
-                $this->innerNode->setAttributeNS($namespace, $qualifiedName, $value);
-            } catch (\DOMException $e) {
-                // The attribute name is invalid for XML
-                // Replace any offending characters with "UHHHHHH" where H are the
-                // uppercase hexadecimal digits of the character's code point
-                if ($prefix !== null) {
-                    $qualifiedName = $this->coerceName($prefix) . ':' . $this->coerceName($localName);
-                } else {
-                    $qualifiedName = $this->coerceName($qualifiedName);
-                }
-
-                $this->innerNode->setAttributeNS($namespace, $qualifiedName, $value);
-            }
-        }*/
-
         // If you create an id attribute this way it won't be used by PHP in
         // getElementById, so let's fix that.
         if ($namespace === null && $qualifiedName === 'id') {
diff --git a/tests/cases/TestDOMTokenList.php b/tests/cases/TestDOMTokenList.php
new file mode 100644
index 0000000..44bcda4
--- /dev/null
+++ b/tests/cases/TestDOMTokenList.php
@@ -0,0 +1,224 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM\TestCase;
+
+use MensBeam\HTML\DOM\{
+    Document,
+    DOMException,
+    Element,
+    Node,
+    Text,
+    XMLDocument
+};
+
+
+/** @covers \MensBeam\HTML\DOM\DOMTokenList */
+class TestDOMTokenList extends \PHPUnit\Framework\TestCase {
+    public function provideMethod_add_remove_replace_toggle__errors(): iterable {
+        return [
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->add('');
+            }, DOMException::SYNTAX_ERROR ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->remove('');
+            }, DOMException::SYNTAX_ERROR ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->replace('ack', '');
+            }, DOMException::SYNTAX_ERROR ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->toggle('');
+            }, DOMException::SYNTAX_ERROR ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->add('fail fail');
+            }, DOMException::INVALID_CHARACTER ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->remove('fail fail');
+            }, DOMException::INVALID_CHARACTER ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->replace('ack', 'fail fail');
+            }, DOMException::INVALID_CHARACTER ],
+            [ function() {
+                $d = new Document();
+                $e = $d->createElement('html');
+                $e->classList->toggle('fail fail');
+            }, DOMException::INVALID_CHARACTER ]
+        ];
+    }
+
+    /** @dataProvider provideMethod_add_remove_replace_toggle__errors */
+    public function testMethod_add_remove_replace_toggle__errors(\Closure $closure, int $errorCode): void {
+        $this->expectException(DOMException::class);
+        $this->expectExceptionCode($errorCode);
+        $closure();
+    }
+
+
+    /**
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::contains
+     *
+     * @covers \MensBeam\HTML\DOM\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Document::createElement
+     * @covers \MensBeam\HTML\DOM\DOMImplementation::__construct
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::__construct
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::__toString
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::add
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::attributeChange
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::parseOrderedSet
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::update
+     * @covers \MensBeam\HTML\DOM\Element::__construct
+     * @covers \MensBeam\HTML\DOM\Element::__get_classList
+     * @covers \MensBeam\HTML\DOM\Node::__construct
+     * @covers \MensBeam\HTML\DOM\Node::appendChild
+     * @covers \MensBeam\HTML\DOM\Node::getInnerDocument
+     * @covers \MensBeam\HTML\DOM\Node::getInnerNode
+     * @covers \MensBeam\HTML\DOM\Node::getRootNode
+     * @covers \MensBeam\HTML\DOM\Node::postInsertionBugFixes
+     * @covers \MensBeam\HTML\DOM\Node::preInsertionBugFixes
+     * @covers \MensBeam\HTML\DOM\Node::preInsertionValidity
+     * @covers \MensBeam\HTML\DOM\Inner\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Inner\Document::getWrapperNode
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::get
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::has
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::key
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::set
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::createFromProtectedConstructor
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::getProtectedProperty
+     */
+    public function testMethod_contains() {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertTrue($e->classList->contains('ack'));
+        $this->assertFalse($e->classList->contains('fail'));
+    }
+
+
+    public function testMethod_count(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertSame(4, count($e->classList));
+    }
+
+
+    public function testMethod_item(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertNull($e->classList->item(42));
+    }
+
+
+    public function testMethod_replace(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->setAttribute('class', 'ook eek ack ookeek');
+        $this->assertTrue($e->classList->replace('ack', 'what'));
+        $this->assertSame('ook eek what ookeek', $e->classList->value);
+        $this->assertSame('ook eek what ookeek', $e->getAttribute('class'));
+        $this->assertFalse($e->classList->replace('fail', 'eekook'));
+    }
+
+
+    public function testMethod_remove(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->setAttribute('class', 'ook eek ack ookeek');
+        $e->classList->remove('ack');
+        $this->assertSame('ook eek ookeek', $e->classList->value);
+        $this->assertSame('ook eek ookeek', $e->getAttribute('class'));
+    }
+
+
+    public function testMethod_supports(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertTrue($e->classList->supports('ack'));
+    }
+
+
+    public function testMethod_toggle(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->setAttribute('class', 'ook eek ack ookeek');
+        $this->assertFalse($e->classList->toggle('ack'));
+        $this->assertSame('ook eek ookeek', $e->classList->value);
+        $this->assertSame('ook eek ookeek', $e->getAttribute('class'));
+        $this->assertTrue($e->classList->toggle('ack'));
+        $this->assertSame('ook eek ookeek ack', $e->classList->value);
+        $this->assertSame('ook eek ookeek ack', $e->getAttribute('class'));
+        $this->assertTrue($e->classList->toggle('ack', true));
+        $this->assertSame('ook eek ookeek ack', $e->classList->value);
+        $this->assertSame('ook eek ookeek ack', $e->getAttribute('class'));
+        $this->assertFalse($e->classList->toggle('eekook', false));
+        $this->assertSame('ook eek ookeek ack', $e->classList->value);
+        $this->assertSame('ook eek ookeek ack', $e->getAttribute('class'));
+        $this->assertTrue($e->classList->toggle('eekook', true));
+        $this->assertSame('ook eek ookeek ack eekook', $e->classList->value);
+        $this->assertSame('ook eek ookeek ack eekook', $e->getAttribute('class'));
+    }
+
+
+    public function testProcess_iteration(): void {
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+
+        foreach ($e->classList as $key => $className) {
+            $this->assertSame($className, $e->classList[$key]);
+            // test offsetExists
+            $this->assertTrue(isset($e->classList[$key]));
+        }
+    }
+
+
+    public function testProperty_value(): void {
+        // Test it with and without an attached document element
+        $d = new Document();
+        $e = $d->createElement('html');
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertSame('ook eek ack ookeek', $e->classList->value);
+        $this->assertSame('ook eek ack ookeek', $e->getAttribute('class'));
+        $e->classList->value = 'omg wtf bbq lol zor bor xxx';
+        $this->assertSame('lol', $e->classList[3]);
+        $this->assertSame('omg wtf bbq lol zor bor xxx', $e->classList->value);
+        $this->assertSame('omg wtf bbq lol zor bor xxx', $e->getAttribute('class'));
+        $e->classList->value = '';
+        $this->assertSame('', $e->classList->value);
+        $this->assertSame('', $e->getAttribute('class'));
+
+        $d = new Document();
+        $e = $d->appendChild($d->createElement('html'));
+        $e->classList->add('ook', 'eek', 'ack', 'ookeek');
+        $this->assertSame('ook eek ack ookeek', $e->classList->value);
+        $this->assertSame('ook eek ack ookeek', $e->getAttribute('class'));
+        $e->classList->value = 'omg wtf bbq lol zor bor xxx';
+        $this->assertSame('lol', $e->classList[3]);
+        $this->assertSame('omg wtf bbq lol zor bor xxx', $e->classList->value);
+        $this->assertSame('omg wtf bbq lol zor bor xxx', $e->getAttribute('class'));
+        $e->classList->value = '';
+        $this->assertSame('', $e->classList->value);
+        $this->assertSame('', $e->getAttribute('class'));
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/TestElement.php b/tests/cases/TestElement.php
index 9ed00e5..bb89fd9 100644
--- a/tests/cases/TestElement.php
+++ b/tests/cases/TestElement.php
@@ -514,6 +514,76 @@ class TestElement extends \PHPUnit\Framework\TestCase {
     }
 
 
+    /**
+     * @covers \MensBeam\HTML\DOM\Element::__get_classList
+     * 
+     * @covers \MensBeam\HTML\DOM\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Document::__get_documentElement
+     * @covers \MensBeam\HTML\DOM\Document::load
+     * @covers \MensBeam\HTML\DOM\DOMImplementation::__construct
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::__construct
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::__get_length
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::attributeChange
+     * @covers \MensBeam\HTML\DOM\DOMTokenList::parseOrderedSet
+     * @covers \MensBeam\HTML\DOM\Element::__construct
+     * @covers \MensBeam\HTML\DOM\Node::__construct
+     * @covers \MensBeam\HTML\DOM\Node::hasChildNodes
+     * @covers \MensBeam\HTML\DOM\Inner\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Inner\Document::getWrapperNode
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::get
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::has
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::key
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::set
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::createFromProtectedConstructor
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::getProtectedProperty
+     */
+    public function testProperty_classList() {
+        $d = new Document('<!DOCTYPE html><html class="ook eek ack foo bar"></html>', 'UTF-8');
+        $documentElement = $d->documentElement;
+        $this->assertEquals(5, $documentElement->classList->length);
+    }
+
+
+    /**
+     * @covers \MensBeam\HTML\DOM\Element::__get_className
+     * @covers \MensBeam\HTML\DOM\Element::__set_className
+     *
+     * @covers \MensBeam\HTML\DOM\Attr::__get_value
+     * @covers \MensBeam\HTML\DOM\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Document::createElement
+     * @covers \MensBeam\HTML\DOM\DOMImplementation::__construct
+     * @covers \MensBeam\HTML\DOM\Element::__construct
+     * @covers \MensBeam\HTML\DOM\Element::__get_namespaceURI
+     * @covers \MensBeam\HTML\DOM\Element::getAttribute
+     * @covers \MensBeam\HTML\DOM\Element::getAttributeNode
+     * @covers \MensBeam\HTML\DOM\Element::setAttribute
+     * @covers \MensBeam\HTML\DOM\Node::__construct
+     * @covers \MensBeam\HTML\DOM\Node::__get_ownerDocument
+     * @covers \MensBeam\HTML\DOM\Node::appendChild
+     * @covers \MensBeam\HTML\DOM\Node::getInnerDocument
+     * @covers \MensBeam\HTML\DOM\Node::getInnerNode
+     * @covers \MensBeam\HTML\DOM\Node::getRootNode
+     * @covers \MensBeam\HTML\DOM\Node::postInsertionBugFixes
+     * @covers \MensBeam\HTML\DOM\Node::preInsertionBugFixes
+     * @covers \MensBeam\HTML\DOM\Node::preInsertionValidity
+     * @covers \MensBeam\HTML\DOM\Inner\Document::__construct
+     * @covers \MensBeam\HTML\DOM\Inner\Document::__get_wrapperNode
+     * @covers \MensBeam\HTML\DOM\Inner\Document::getWrapperNode
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::get
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::has
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::key
+     * @covers \MensBeam\HTML\DOM\Inner\NodeCache::set
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::createFromProtectedConstructor
+     * @covers \MensBeam\HTML\DOM\Inner\Reflection::getProtectedProperty
+     */
+    public function testProperty_className() {
+        $d = new Document();
+        $documentElement = $d->appendChild($d->createElement('html'));
+        $documentElement->className = 'ook';
+        $this->assertSame('ook', $documentElement->className);
+    }
+
+
     /**
      * @covers \MensBeam\HTML\DOM\Element::__get_id
      * @covers \MensBeam\HTML\DOM\Element::__set_id
diff --git a/tests/phpunit.dist.xml b/tests/phpunit.dist.xml
index a054222..d84e8d0 100644
--- a/tests/phpunit.dist.xml
+++ b/tests/phpunit.dist.xml
@@ -18,6 +18,7 @@
     <testsuite name="DOM">
       <file>cases/TestDocument.php</file>
       <file>cases/TestDocumentOrElement.php</file>
+      <file>cases/TestDOMTokenList.php</file>
       <file>cases/TestElement.php</file>
       <file>cases/TestNode.php</file>
     </testsuite>
diff --git a/vendor-bin/phpunit/composer.lock b/vendor-bin/phpunit/composer.lock
index 8b462ee..31012f1 100644
--- a/vendor-bin/phpunit/composer.lock
+++ b/vendor-bin/phpunit/composer.lock
@@ -1801,6 +1801,7 @@
                     "type": "github"
                 }
             ],
+            "abandoned": true,
             "time": "2020-09-28T06:45:17+00:00"
         },
         {
diff --git a/vendor-bin/robo/composer.lock b/vendor-bin/robo/composer.lock
index 8325ff3..e118f79 100644
--- a/vendor-bin/robo/composer.lock
+++ b/vendor-bin/robo/composer.lock
@@ -855,16 +855,16 @@
         },
         {
             "name": "symfony/deprecation-contracts",
-            "version": "v2.4.0",
+            "version": "v2.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/deprecation-contracts.git",
-                "reference": "5f38c8804a9e97d23e0c8d63341088cd8a22d627"
+                "reference": "6f981ee24cf69ee7ce9736146d1c57c2780598a8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/deprecation-contracts/zipball/5f38c8804a9e97d23e0c8d63341088cd8a22d627",
-                "reference": "5f38c8804a9e97d23e0c8d63341088cd8a22d627",
+                "url": "https://api.github.com/repos/symfony/deprecation-contracts/zipball/6f981ee24cf69ee7ce9736146d1c57c2780598a8",
+                "reference": "6f981ee24cf69ee7ce9736146d1c57c2780598a8",
                 "shasum": ""
             },
             "require": {
@@ -873,7 +873,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "2.4-dev"
+                    "dev-main": "2.5-dev"
                 },
                 "thanks": {
                     "name": "symfony/contracts",
@@ -902,7 +902,7 @@
             "description": "A generic function and convention to trigger deprecation notices",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/deprecation-contracts/tree/v2.4.0"
+                "source": "https://github.com/symfony/deprecation-contracts/tree/v2.5.0"
             },
             "funding": [
                 {
@@ -918,20 +918,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-03-23T23:28:01+00:00"
+            "time": "2021-07-12T14:48:14+00:00"
         },
         {
             "name": "symfony/event-dispatcher",
-            "version": "v5.3.7",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/event-dispatcher.git",
-                "reference": "ce7b20d69c66a20939d8952b617506a44d102130"
+                "reference": "661a7a6e085394f8513945669e31f7c1338a7e69"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/event-dispatcher/zipball/ce7b20d69c66a20939d8952b617506a44d102130",
-                "reference": "ce7b20d69c66a20939d8952b617506a44d102130",
+                "url": "https://api.github.com/repos/symfony/event-dispatcher/zipball/661a7a6e085394f8513945669e31f7c1338a7e69",
+                "reference": "661a7a6e085394f8513945669e31f7c1338a7e69",
                 "shasum": ""
             },
             "require": {
@@ -987,7 +987,7 @@
             "description": "Provides tools that allow your application components to communicate with each other by dispatching events and listening to them",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/event-dispatcher/tree/v5.3.7"
+                "source": "https://github.com/symfony/event-dispatcher/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1003,20 +1003,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-08-04T21:20:46+00:00"
+            "time": "2021-11-17T12:16:12+00:00"
         },
         {
             "name": "symfony/event-dispatcher-contracts",
-            "version": "v2.4.0",
+            "version": "v2.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/event-dispatcher-contracts.git",
-                "reference": "69fee1ad2332a7cbab3aca13591953da9cdb7a11"
+                "reference": "66bea3b09be61613cd3b4043a65a8ec48cfa6d2a"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/event-dispatcher-contracts/zipball/69fee1ad2332a7cbab3aca13591953da9cdb7a11",
-                "reference": "69fee1ad2332a7cbab3aca13591953da9cdb7a11",
+                "url": "https://api.github.com/repos/symfony/event-dispatcher-contracts/zipball/66bea3b09be61613cd3b4043a65a8ec48cfa6d2a",
+                "reference": "66bea3b09be61613cd3b4043a65a8ec48cfa6d2a",
                 "shasum": ""
             },
             "require": {
@@ -1029,7 +1029,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "2.4-dev"
+                    "dev-main": "2.5-dev"
                 },
                 "thanks": {
                     "name": "symfony/contracts",
@@ -1066,7 +1066,7 @@
                 "standards"
             ],
             "support": {
-                "source": "https://github.com/symfony/event-dispatcher-contracts/tree/v2.4.0"
+                "source": "https://github.com/symfony/event-dispatcher-contracts/tree/v2.5.0"
             },
             "funding": [
                 {
@@ -1082,7 +1082,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-03-23T23:28:01+00:00"
+            "time": "2021-07-12T14:48:14+00:00"
         },
         {
             "name": "symfony/filesystem",
@@ -1697,16 +1697,16 @@
         },
         {
             "name": "symfony/process",
-            "version": "v5.3.7",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/process.git",
-                "reference": "38f26c7d6ed535217ea393e05634cb0b244a1967"
+                "reference": "6c99204de85d04ca17f16c466fc61896960b0636"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/process/zipball/38f26c7d6ed535217ea393e05634cb0b244a1967",
-                "reference": "38f26c7d6ed535217ea393e05634cb0b244a1967",
+                "url": "https://api.github.com/repos/symfony/process/zipball/6c99204de85d04ca17f16c466fc61896960b0636",
+                "reference": "6c99204de85d04ca17f16c466fc61896960b0636",
                 "shasum": ""
             },
             "require": {
@@ -1739,7 +1739,7 @@
             "description": "Executes commands in sub-processes",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/process/tree/v5.3.7"
+                "source": "https://github.com/symfony/process/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1755,25 +1755,29 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-08-04T21:20:46+00:00"
+            "time": "2021-11-17T12:16:12+00:00"
         },
         {
             "name": "symfony/service-contracts",
-            "version": "v2.4.0",
+            "version": "v2.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/service-contracts.git",
-                "reference": "f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb"
+                "reference": "1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/service-contracts/zipball/f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb",
-                "reference": "f040a30e04b57fbcc9c6cbcf4dbaa96bd318b9bb",
+                "url": "https://api.github.com/repos/symfony/service-contracts/zipball/1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc",
+                "reference": "1ab11b933cd6bc5464b08e81e2c5b07dec58b0fc",
                 "shasum": ""
             },
             "require": {
                 "php": ">=7.2.5",
-                "psr/container": "^1.1"
+                "psr/container": "^1.1",
+                "symfony/deprecation-contracts": "^2.1"
+            },
+            "conflict": {
+                "ext-psr": "<1.1|>=2"
             },
             "suggest": {
                 "symfony/service-implementation": ""
@@ -1781,7 +1785,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "2.4-dev"
+                    "dev-main": "2.5-dev"
                 },
                 "thanks": {
                     "name": "symfony/contracts",
@@ -1818,7 +1822,7 @@
                 "standards"
             ],
             "support": {
-                "source": "https://github.com/symfony/service-contracts/tree/v2.4.0"
+                "source": "https://github.com/symfony/service-contracts/tree/v2.5.0"
             },
             "funding": [
                 {
@@ -1834,7 +1838,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-04-01T10:43:52+00:00"
+            "time": "2021-11-04T16:48:04+00:00"
         },
         {
             "name": "symfony/string",
@@ -1921,16 +1925,16 @@
         },
         {
             "name": "symfony/yaml",
-            "version": "v5.3.6",
+            "version": "v5.3.11",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
-                "reference": "4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7"
+                "reference": "226638aa877bc4104e619a15f27d8141cd6b4e4a"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/yaml/zipball/4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7",
-                "reference": "4500fe63dc9c6ffc32d3b1cb0448c329f9c814b7",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/226638aa877bc4104e619a15f27d8141cd6b4e4a",
+                "reference": "226638aa877bc4104e619a15f27d8141cd6b4e4a",
                 "shasum": ""
             },
             "require": {
@@ -1976,7 +1980,7 @@
             "description": "Loads and dumps YAML files",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/yaml/tree/v5.3.6"
+                "source": "https://github.com/symfony/yaml/tree/v5.3.11"
             },
             "funding": [
                 {
@@ -1992,7 +1996,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-07-29T06:20:01+00:00"
+            "time": "2021-11-20T16:42:42+00:00"
         }
     ],
     "packages-dev": [],