diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0bff653e4..d5c5d2f78 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Breaking change
 - Core infrastructure is now contained in a new package DocumentFormat.OpenXml.Framework. Typed classes are still in DocumentFormat.OpenXml. This means that you may reference DocumentFormat.OpenXml and still compile the same types, but if you want a smaller package, you may rely on just the framework package. 
+- Removed mutable properties on OpenXmlAttribute and marked as `readonly`
 
 ## [2.20.0]
 
diff --git a/src/DocumentFormat.OpenXml.Framework/OpenXmlAttribute.cs b/src/DocumentFormat.OpenXml.Framework/OpenXmlAttribute.cs
index 9eb70f9f5..5d921495f 100644
--- a/src/DocumentFormat.OpenXml.Framework/OpenXmlAttribute.cs
+++ b/src/DocumentFormat.OpenXml.Framework/OpenXmlAttribute.cs
@@ -11,18 +11,13 @@ namespace DocumentFormat.OpenXml
     /// <summary>
     /// Represents an Open XML attribute.
     /// </summary>
-    public struct OpenXmlAttribute : IEquatable<OpenXmlAttribute>
+    public readonly struct OpenXmlAttribute : IEquatable<OpenXmlAttribute>
     {
-        private const string ObsoleteMessage = "OpenXmlAttribute is a struct so setters may not behave as you might expect. Mutable setters will be removed in a future version.";
-
-        private string? _value;
-        private string _prefix;
-
         internal OpenXmlAttribute(in OpenXmlQualifiedName qname, string prefix, string? value)
         {
             QName = qname;
-            _value = value;
-            _prefix = prefix;
+            Value = value;
+            Prefix = prefix;
         }
 
         /// <summary>
@@ -41,8 +36,8 @@ public OpenXmlAttribute(string qualifiedName, string namespaceUri, string? value
             var parsed = PrefixName.Parse(qualifiedName);
 
             QName = new(namespaceUri, parsed.Name);
-            _prefix = parsed.Prefix;
-            _value = value;
+            Prefix = parsed.Prefix;
+            Value = value;
         }
 
         /// <summary>
@@ -60,49 +55,29 @@ public OpenXmlAttribute(string prefix, string localName, string namespaceUri, st
             }
 
             QName = new(namespaceUri, localName);
-            _prefix = prefix;
-            _value = value;
+            Prefix = prefix;
+            Value = value;
         }
 
         /// <summary>
-        /// Gets or sets the namespace URI of the current attribute.
+        /// Gets the namespace URI of the current attribute.
         /// </summary>
-        public string NamespaceUri
-        {
-            get => QName.Namespace.Uri;
-            [Obsolete(ObsoleteMessage)]
-            set => QName = new(value, LocalName);
-        }
+        public string NamespaceUri => QName.Namespace.Uri;
 
         /// <summary>
-        /// Gets or sets the local name of the attribute.
+        /// Gets the local name of the attribute.
         /// </summary>
-        public string LocalName
-        {
-            get => QName.Name;
-            [Obsolete(ObsoleteMessage)]
-            set => QName = new(QName.Namespace, value);
-        }
+        public string LocalName => QName.Name;
 
         /// <summary>
-        /// Gets or sets the namespace prefix of the current attribute.
+        /// Gets the namespace prefix of the current attribute.
         /// </summary>
-        public string Prefix
-        {
-            get => _prefix;
-            [Obsolete(ObsoleteMessage)]
-            set => _prefix = value;
-        }
+        public string Prefix { get; }
 
         /// <summary>
-        /// Gets or sets the text value of the attribute.
+        /// Gets the text value of the attribute.
         /// </summary>
-        public string? Value
-        {
-            get => _value;
-            [Obsolete(ObsoleteMessage)]
-            set => _value = value;
-        }
+        public string? Value { get; }
 
         /// <summary>
         /// Gets the qualified name of the attribute.
@@ -114,7 +89,7 @@ public string? Value
         /// </summary>
         public XName XName => XName.Get(LocalName, QName.Namespace.Uri);
 
-        internal OpenXmlQualifiedName QName { get; private set; }
+        internal OpenXmlQualifiedName QName { get; }
 
         /// <summary>
         /// Determines if this instance of an OpenXmlAttribute structure is equal to the specified instance of an OpenXmlAttribute structure.
@@ -124,7 +99,7 @@ public string? Value
         public bool Equals(OpenXmlAttribute other)
             => string.Equals(Value, other.Value, StringComparison.Ordinal)
             && QName.Equals(other.QName)
-            && string.Equals(_prefix, other._prefix, StringComparison.Ordinal);
+            && string.Equals(Prefix, other.Prefix, StringComparison.Ordinal);
 
         /// <summary>
         /// Determines if two instances of OpenXmlAttribute structures are equal.
@@ -162,7 +137,7 @@ public override int GetHashCode()
 
             hashcode.Add(Value, StringComparer.Ordinal);
             hashcode.Add(QName);
-            hashcode.Add(_prefix, StringComparer.Ordinal);
+            hashcode.Add(Prefix, StringComparer.Ordinal);
 
             return hashcode.ToHashCode();
         }
diff --git a/test/DocumentFormat.OpenXml.Tests/OpenXmlDomTest/OpenXmlCompositeElementTestClass.cs b/test/DocumentFormat.OpenXml.Tests/OpenXmlDomTest/OpenXmlCompositeElementTestClass.cs
index b538ae9ab..b33bb2ede 100644
--- a/test/DocumentFormat.OpenXml.Tests/OpenXmlDomTest/OpenXmlCompositeElementTestClass.cs
+++ b/test/DocumentFormat.OpenXml.Tests/OpenXmlDomTest/OpenXmlCompositeElementTestClass.cs
@@ -587,15 +587,9 @@ public void OpenXmlAttributeValueTypeTest()
 
             Log.Comment("Constructing OpenXmlAttribute w:rsidR and assigning it to another variable...");
             var wrsidR = new OpenXmlAttribute("w", "rsidR", "http://schemas.openxmlformats.org/wordprocessingml/2006/main", "00B327F7");
-            var wrsidP = wrsidR;
-            Log.VerifyTrue(wrsidP == wrsidR, "The assigned OpenXmlAttribute variable is NOT equal to original one.");
-
-#pragma warning disable CS0618 // Type or member is obsolete
-            wrsidP.LocalName = "rsidP";
-            wrsidP.Value = "00EC35BB";
-#pragma warning restore CS0618 // Type or member is obsolete
-            Log.Comment("Assigned new LocalName: {0} with ByValue: {1} and comparing it with original w:rsidR", wrsidP.LocalName, wrsidP.Value);
-            Log.VerifyFalse(wrsidP == wrsidR, "The assigned OpenXmlAttribute variable IS equal to original one.");
+            var wrsidP = new OpenXmlAttribute("w", "rsidP", "http://schemas.openxmlformats.org/wordprocessingml/2006/main", "00EC35BB");
+
+            Assert.NotEqual(wrsidP, wrsidR);
         }
 
         [Fact]
diff --git a/test/DocumentFormat.OpenXml.Tests/ofapiTest/OpenXmlElementTest.cs b/test/DocumentFormat.OpenXml.Tests/ofapiTest/OpenXmlElementTest.cs
index c6867aec1..5bb6c1de3 100644
--- a/test/DocumentFormat.OpenXml.Tests/ofapiTest/OpenXmlElementTest.cs
+++ b/test/DocumentFormat.OpenXml.Tests/ofapiTest/OpenXmlElementTest.cs
@@ -433,7 +433,6 @@ public void DefaultOpenXmlAttributeTest()
         [Fact]
         public void OpenXmlAttributeTest()
         {
-#pragma warning disable CS0618 // Type or member is obsolete
             var target = new OpenXmlAttribute("test", "http://test", "test", "value");
             var other = new OpenXmlAttribute("test", "http://test", "test", "value");
 
@@ -444,8 +443,13 @@ public void OpenXmlAttributeTest()
             Assert.True(target.Equals((object)other));
             Assert.True(Equals(target, other));
             Assert.Equal(target.GetHashCode(), other.GetHashCode());
+        }
 
-            other.Value = "other";
+        [Fact]
+        public void OpenXmlAttributeTestDifferentValues()
+        {
+            var target = new OpenXmlAttribute("test", "http://test", "test", "value");
+            var other = new OpenXmlAttribute("test", "http://test", "test", "other");
 
             Assert.NotEqual(target, other);
             Assert.False(target == other);
@@ -454,18 +458,13 @@ public void OpenXmlAttributeTest()
             Assert.False(target.Equals((object)other));
             Assert.False(Equals(target, other));
             Assert.NotEqual(target.GetHashCode(), other.GetHashCode());
+        }
 
-            other.Value = "value";
-
-            Assert.Equal(target, other);
-            Assert.True(target == other);
-            Assert.False(target != other);
-            Assert.True(target.Equals(other));
-            Assert.True(target.Equals((object)other));
-            Assert.True(Equals(target, other));
-            Assert.Equal(target.GetHashCode(), other.GetHashCode());
-
-            other.Prefix = "t";
+        [Fact]
+        public void OpenXmlAttributeTestDifferentPrefix()
+        {
+            var target = new OpenXmlAttribute("test", "http://test", "test", "value");
+            var other = new OpenXmlAttribute("t", "http://test", "test", "value");
 
             Assert.NotEqual(target, other);
             Assert.False(target == other);
@@ -474,7 +473,6 @@ public void OpenXmlAttributeTest()
             Assert.False(target.Equals((object)other));
             Assert.False(Equals(target, other));
             Assert.NotEqual(target.GetHashCode(), other.GetHashCode());
-#pragma warning restore CS0618 // Type or member is obsolete
         }
 
         /// <summary>