diff --git a/Userland/Libraries/LibWeb/DOM/MutationRecord.cpp b/Userland/Libraries/LibWeb/DOM/MutationRecord.cpp
index 8a1af51767..0bb4aaf86b 100644
--- a/Userland/Libraries/LibWeb/DOM/MutationRecord.cpp
+++ b/Userland/Libraries/LibWeb/DOM/MutationRecord.cpp
@@ -12,12 +12,12 @@
 
 namespace Web::DOM {
 
-JS::NonnullGCPtr<MutationRecord> MutationRecord::create(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, DeprecatedString const& attribute_name, DeprecatedString const& attribute_namespace, DeprecatedString const& old_value)
+JS::NonnullGCPtr<MutationRecord> MutationRecord::create(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, Optional<String> const& attribute_name, Optional<String> const& attribute_namespace, Optional<String> const& old_value)
 {
     return realm.heap().allocate<MutationRecord>(realm, realm, type, target, added_nodes, removed_nodes, previous_sibling, next_sibling, attribute_name, attribute_namespace, old_value);
 }
 
-MutationRecord::MutationRecord(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, DeprecatedString const& attribute_name, DeprecatedString const& attribute_namespace, DeprecatedString const& old_value)
+MutationRecord::MutationRecord(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, Optional<String> const& attribute_name, Optional<String> const& attribute_namespace, Optional<String> const& old_value)
     : PlatformObject(realm)
     , m_type(type)
     , m_target(JS::make_handle(target))
diff --git a/Userland/Libraries/LibWeb/DOM/MutationRecord.h b/Userland/Libraries/LibWeb/DOM/MutationRecord.h
index 690103d3cf..6d89813aec 100644
--- a/Userland/Libraries/LibWeb/DOM/MutationRecord.h
+++ b/Userland/Libraries/LibWeb/DOM/MutationRecord.h
@@ -16,7 +16,7 @@ class MutationRecord : public Bindings::PlatformObject {
     WEB_PLATFORM_OBJECT(MutationRecord, Bindings::PlatformObject);
 
 public:
-    [[nodiscard]] static JS::NonnullGCPtr<MutationRecord> create(JS::Realm&, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, DeprecatedString const& attribute_name, DeprecatedString const& attribute_namespace, DeprecatedString const& old_value);
+    [[nodiscard]] static JS::NonnullGCPtr<MutationRecord> create(JS::Realm&, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, Optional<String> const& attribute_name, Optional<String> const& attribute_namespace, Optional<String> const& old_value);
 
     virtual ~MutationRecord() override;
 
@@ -26,12 +26,12 @@ public:
     NodeList const* removed_nodes() const { return m_removed_nodes; }
     Node const* previous_sibling() const { return m_previous_sibling; }
     Node const* next_sibling() const { return m_next_sibling; }
-    DeprecatedString const& attribute_name() const { return m_attribute_name; }
-    DeprecatedString const& attribute_namespace() const { return m_attribute_namespace; }
-    DeprecatedString const& old_value() const { return m_old_value; }
+    Optional<String> const& attribute_name() const { return m_attribute_name; }
+    Optional<String> const& attribute_namespace() const { return m_attribute_namespace; }
+    Optional<String> const& old_value() const { return m_old_value; }
 
 private:
-    MutationRecord(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, DeprecatedString const& attribute_name, DeprecatedString const& attribute_namespace, DeprecatedString const& old_value);
+    MutationRecord(JS::Realm& realm, FlyString const& type, Node const& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, Optional<String> const& attribute_name, Optional<String> const& attribute_namespace, Optional<String> const& old_value);
 
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
@@ -42,9 +42,9 @@ private:
     JS::GCPtr<NodeList> m_removed_nodes;
     JS::GCPtr<Node> m_previous_sibling;
     JS::GCPtr<Node> m_next_sibling;
-    DeprecatedString m_attribute_name;
-    DeprecatedString m_attribute_namespace;
-    DeprecatedString m_old_value;
+    Optional<String> m_attribute_name;
+    Optional<String> m_attribute_namespace;
+    Optional<String> m_old_value;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/DOM/MutationRecord.idl b/Userland/Libraries/LibWeb/DOM/MutationRecord.idl
index 8e6ccb3054..0914177892 100644
--- a/Userland/Libraries/LibWeb/DOM/MutationRecord.idl
+++ b/Userland/Libraries/LibWeb/DOM/MutationRecord.idl
@@ -1,7 +1,7 @@
 #import <DOM/Node.idl>
 #import <DOM/NodeList.idl>
 
-[Exposed=Window, UseDeprecatedAKString]
+[Exposed=Window]
 interface MutationRecord {
 
     readonly attribute DOMString type;
diff --git a/Userland/Libraries/LibWeb/DOM/Node.cpp b/Userland/Libraries/LibWeb/DOM/Node.cpp
index 38a0cf45ca..a63c41db8f 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Node.cpp
@@ -1530,7 +1530,19 @@ void Node::queue_mutation_record(FlyString const& type, DeprecatedString attribu
     for (auto& interested_observer : interested_observers) {
         // 1. Let record be a new MutationRecord object with its type set to type, target set to target, attributeName set to name, attributeNamespace set to namespace, oldValue set to mappedOldValue,
         //    addedNodes set to addedNodes, removedNodes set to removedNodes, previousSibling set to previousSibling, and nextSibling set to nextSibling.
-        auto record = MutationRecord::create(realm(), type, *this, added_nodes_list, removed_nodes_list, previous_sibling, next_sibling, attribute_name, attribute_namespace, /* mappedOldValue */ interested_observer.value);
+        Optional<String> maybe_attribute_name;
+        if (!attribute_name.is_null())
+            maybe_attribute_name = MUST(String::from_deprecated_string(attribute_name));
+
+        Optional<String> maybe_attribute_namespace;
+        if (!attribute_namespace.is_null())
+            maybe_attribute_namespace = MUST(String::from_deprecated_string(attribute_namespace));
+
+        Optional<String> maybe_interested_observer;
+        if (!interested_observer.value.is_null())
+            maybe_interested_observer = MUST(String::from_deprecated_string(interested_observer.value));
+
+        auto record = MutationRecord::create(realm(), type, *this, added_nodes_list, removed_nodes_list, previous_sibling, next_sibling, maybe_attribute_name, maybe_attribute_namespace, /* mappedOldValue */ maybe_interested_observer);
 
         // 2. Enqueue record to observer’s record queue.
         interested_observer.key->enqueue_record({}, move(record));