diff --git a/.gitignore b/.gitignore
index 0e121215810..41ec32f22cb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,7 @@ docs/api
 *.cache
 .settings
 .DS_Store
+.idea
 launchSettings.json
 package-lock.json
 *.sublime-workspace
diff --git a/src/Microsoft.DocAsCode.Build.Common/MarkdownReader.cs b/src/Microsoft.DocAsCode.Build.Common/MarkdownReader.cs
index a04fb0ef237..d477d28dab0 100644
--- a/src/Microsoft.DocAsCode.Build.Common/MarkdownReader.cs
+++ b/src/Microsoft.DocAsCode.Build.Common/MarkdownReader.cs
@@ -128,7 +128,7 @@ private static Dictionary<string, object> RemoveRequiredProperties(ImmutableDict
         private static bool CheckRequiredProperties(ImmutableDictionary<string, object> properties, IEnumerable<string> requiredKeys, out string message)
         {
             var notExistsKeys = (from key in requiredKeys
-                                 where !properties.Keys.Contains(key)
+                                 where !properties.ContainsKey(key)
                                  select key).ToList();
             if (notExistsKeys.Count > 0)
             {
diff --git a/src/Microsoft.DocAsCode.Build.ManagedReference/BuildOutputs/ApiBuildOutput.cs b/src/Microsoft.DocAsCode.Build.ManagedReference/BuildOutputs/ApiBuildOutput.cs
index 8b78c81f80b..13dff1f0ea0 100644
--- a/src/Microsoft.DocAsCode.Build.ManagedReference/BuildOutputs/ApiBuildOutput.cs
+++ b/src/Microsoft.DocAsCode.Build.ManagedReference/BuildOutputs/ApiBuildOutput.cs
@@ -242,7 +242,7 @@ private static ApiBuildOutput FromModel(ItemViewModel model, Dictionary<string,
                 Conceptual = model.Conceptual,
                 Platform = model.Platform,
                 Attributes = model.Attributes,
-                Metadata = model.Metadata.Concat(metadata.Where(p => !model.Metadata.Keys.Contains(p.Key))).ToDictionary(p => p.Key, p => p.Value),
+                Metadata = model.Metadata.Concat(metadata.Where(p => !model.Metadata.ContainsKey(p.Key))).ToDictionary(p => p.Key, p => p.Value),
             };
             output.DerivedClasses = GetReferenceList(model.DerivedClasses, references, model.SupportedLanguages, true, output.Level + 1);
             return output;
diff --git a/src/Microsoft.DocAsCode.Build.OverwriteDocuments/OverwriteDocumentModelCreater.cs b/src/Microsoft.DocAsCode.Build.OverwriteDocuments/OverwriteDocumentModelCreater.cs
index d3b8854805f..c17e3e49686 100644
--- a/src/Microsoft.DocAsCode.Build.OverwriteDocuments/OverwriteDocumentModelCreater.cs
+++ b/src/Microsoft.DocAsCode.Build.OverwriteDocuments/OverwriteDocumentModelCreater.cs
@@ -52,7 +52,7 @@ internal static Dictionary<object, object> ConvertYamlCodeBlock(string yamlCodeB
             catch (Exception ex)
             {
                 throw new MarkdownFragmentsException(
-                    $"Encountered an invalid YAML code block: {ex.Message}",
+                    $"Encountered an invalid YAML code block: {ex.ToString()}",
                     yamlCodeBlockSource.Line,
                     ex);
             }
@@ -116,8 +116,8 @@ private void FindOrCreateObject(Dictionary<object, object> currentObject, Block
                     {
                         object value;
                         var goodItems = (from item in listObject
-                                         where item is Dictionary<object, object> 
-                                            && ((Dictionary<object, object>)item).TryGetValue(segment.Key, out value) 
+                                         where item is Dictionary<object, object>
+                                            && ((Dictionary<object, object>)item).TryGetValue(segment.Key, out value)
                                             && ((string)value).Equals(segment.Value)
                                          select (Dictionary<object, object>)item).ToList();
                         if (goodItems.Count > 0)
diff --git a/src/Microsoft.DocAsCode.Build.TableOfContents/TocHelper.cs b/src/Microsoft.DocAsCode.Build.TableOfContents/TocHelper.cs
index acbc9c3b820..903a1f9ab99 100644
--- a/src/Microsoft.DocAsCode.Build.TableOfContents/TocHelper.cs
+++ b/src/Microsoft.DocAsCode.Build.TableOfContents/TocHelper.cs
@@ -111,7 +111,7 @@ public static TocItemViewModel LoadYamlToc(string file)
             }
             catch (Exception ex)
             {
-                throw new NotSupportedException($"{file} is not a valid TOC file, detail: {ex.Message}.", ex);
+                throw new NotSupportedException($"{file} is not a valid TOC file, detail: {ex.ToString()}.", ex);
             }
             if (obj is TocViewModel vm)
             {
diff --git a/src/Microsoft.DocAsCode.Build.UniversalReference/ModelConverter.cs b/src/Microsoft.DocAsCode.Build.UniversalReference/ModelConverter.cs
index 11a82fd2465..dcd369fe7f6 100644
--- a/src/Microsoft.DocAsCode.Build.UniversalReference/ModelConverter.cs
+++ b/src/Microsoft.DocAsCode.Build.UniversalReference/ModelConverter.cs
@@ -256,7 +256,7 @@ ApiBuildOutput ToItemApiBuildOutput(ItemViewModel src)
                     Conceptual = src.Conceptual,
 
                     Platform = ToApiListInDevLangs(src.Platform, src.PlatformInDevLangs, supportedLanguages),
-                    Metadata = model.Metadata?.Concat(src.Metadata.Where(p => !model.Metadata.Keys.Contains(p.Key))).ToDictionary(p => p.Key, p => p.Value) ?? src.Metadata,
+                    Metadata = model.Metadata?.Concat(src.Metadata.Where(p => !model.Metadata.ContainsKey(p.Key))).ToDictionary(p => p.Key, p => p.Value) ?? src.Metadata,
                 };
             }
 
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/Microsoft.DocAsCode.YamlSerialization.csproj b/src/Microsoft.DocAsCode.YamlSerialization/Microsoft.DocAsCode.YamlSerialization.csproj
index df6645cfa97..d5e9dbd99a0 100644
--- a/src/Microsoft.DocAsCode.YamlSerialization/Microsoft.DocAsCode.YamlSerialization.csproj
+++ b/src/Microsoft.DocAsCode.YamlSerialization/Microsoft.DocAsCode.YamlSerialization.csproj
@@ -1,5 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <ItemGroup>
-    <PackageReference Include="YamlDotNet" Version="6.0.0" />
+    <PackageReference Include="YamlDotNet" Version="12.3.1" />
   </ItemGroup>
 </Project>
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/ObjectGraphVisitors/ExclusiveObjectGraphVisitor.cs b/src/Microsoft.DocAsCode.YamlSerialization/ObjectGraphVisitors/ExclusiveObjectGraphVisitor.cs
new file mode 100644
index 00000000000..823f6342bfc
--- /dev/null
+++ b/src/Microsoft.DocAsCode.YamlSerialization/ObjectGraphVisitors/ExclusiveObjectGraphVisitor.cs
@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.YamlSerialization.ObjectGraphVisitors
+{
+    using System;
+    using System.ComponentModel;
+    using YamlDotNet.Core;
+    using YamlDotNet.Serialization;
+    using YamlDotNet.Serialization.ObjectGraphVisitors;
+
+    /// <summary>
+    /// YamlDotNet behavior has changed since 6.x so a custom version which doesn't check on EnterMapping(IObjectDescriptor).
+    /// </summary>
+    internal sealed class ExclusiveObjectGraphVisitor : ChainedObjectGraphVisitor
+    {
+        public ExclusiveObjectGraphVisitor(IObjectGraphVisitor<IEmitter> nextVisitor)
+            : base(nextVisitor)
+        {
+        }
+
+        private static object GetDefault(Type type)
+        {
+            return type.IsValueType ? Activator.CreateInstance(type) : null;
+        }
+
+        public override bool EnterMapping(IPropertyDescriptor key, IObjectDescriptor value, IEmitter context)
+        {
+            var defaultValueAttribute = key.GetCustomAttribute<DefaultValueAttribute>();
+            object defaultValue = defaultValueAttribute != null
+                ? defaultValueAttribute.Value
+                : GetDefault(key.Type);
+
+            return !Equals(value.Value, defaultValue) && base.EnterMapping(key, value, context);
+        }
+    }
+}
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/SerializationOptions.cs b/src/Microsoft.DocAsCode.YamlSerialization/SerializationOptions.cs
new file mode 100644
index 00000000000..9e840ee27c9
--- /dev/null
+++ b/src/Microsoft.DocAsCode.YamlSerialization/SerializationOptions.cs
@@ -0,0 +1,42 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.DocAsCode.YamlSerialization
+{
+    using System;
+
+    /// <summary>Options that control the serialization process.</summary>
+    [Flags]
+    public enum SerializationOptions
+    {
+        /// <summary>Serializes using the default options</summary>
+        None = 0,
+        /// <summary>
+        /// Ensures that it will be possible to deserialize the serialized objects.
+        /// </summary>
+        Roundtrip = 1,
+        /// <summary>
+        /// If this flag is specified, if the same object appears more than once in the
+        /// serialization graph, it will be serialized each time instead of just once.
+        /// </summary>
+        /// <remarks>
+        /// If the serialization graph contains circular references and this flag is set,
+        /// a StackOverflowException will be thrown.
+        /// If this flag is not set, there is a performance penalty because the entire
+        /// object graph must be walked twice.
+        /// </remarks>
+        DisableAliases = 2,
+        /// <summary>
+        /// Forces every value to be serialized, even if it is the default value for that type.
+        /// </summary>
+        EmitDefaults = 4,
+        /// <summary>
+        /// Ensures that the result of the serialization is valid JSON.
+        /// </summary>
+        JsonCompatible = 8,
+        /// <summary>
+        /// Use the static type of values instead of their actual type.
+        /// </summary>
+        DefaultToStaticType = 16, // 0x00000010
+    }
+}
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/TypeInspectors/EmitTypeInspector.cs b/src/Microsoft.DocAsCode.YamlSerialization/TypeInspectors/EmitTypeInspector.cs
index b4f14322459..cd01594b2d3 100644
--- a/src/Microsoft.DocAsCode.YamlSerialization/TypeInspectors/EmitTypeInspector.cs
+++ b/src/Microsoft.DocAsCode.YamlSerialization/TypeInspectors/EmitTypeInspector.cs
@@ -18,8 +18,8 @@ namespace Microsoft.DocAsCode.YamlSerialization.TypeInspectors
 
     public class EmitTypeInspector : ExtensibleTypeInspectorSkeleton
     {
-        private static readonly ConcurrentDictionary<Type, CachingItem> _cache =
-            new ConcurrentDictionary<Type, CachingItem>();
+        private static readonly ConcurrentDictionary<Type, CachingItem> _cache = new();
+        private static readonly ConcurrentDictionary<Type, List<IPropertyDescriptor>> _propertyDescriptorCache = new();
         private readonly ITypeResolver _resolver;
 
         public EmitTypeInspector(ITypeResolver resolver)
@@ -34,17 +34,22 @@ public override IEnumerable<IPropertyDescriptor> GetProperties(Type type, object
             {
                 throw item.Error;
             }
-            var result = from p in item.Properies select (IPropertyDescriptor)new EmitPropertyDescriptor(p, _resolver);
             if (container == null || item.ExtensibleProperies.Count == 0)
             {
-                return result;
+                // all static information
+                return _propertyDescriptorCache.GetOrAdd(type, GetPropertyDescriptors(item).ToList());
             }
-            return result.Concat(
+            return GetPropertyDescriptors(item).Concat(
                 from ep in item.ExtensibleProperies
                 from key in ep.GetAllKeys(container) ?? Enumerable.Empty<string>()
                 select new ExtensiblePropertyDescriptor(ep, ep.Prefix + key, _resolver));
         }
 
+        private IEnumerable<IPropertyDescriptor> GetPropertyDescriptors(CachingItem item)
+        {
+            return from p in item.Properies select new EmitPropertyDescriptor(p, _resolver);
+        }
+
         public override IPropertyDescriptor GetProperty(Type type, object container, string name)
         {
             var item = _cache.GetOrAdd(type, CachingItem.Create);
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/YamlDeserializer.cs b/src/Microsoft.DocAsCode.YamlSerialization/YamlDeserializer.cs
index cea35d59896..538fe807031 100644
--- a/src/Microsoft.DocAsCode.YamlSerialization/YamlDeserializer.cs
+++ b/src/Microsoft.DocAsCode.YamlSerialization/YamlDeserializer.cs
@@ -28,21 +28,19 @@ namespace Microsoft.DocAsCode.YamlSerialization
     /// </summary>
     public sealed class YamlDeserializer
     {
-        private static Dictionary<string, Type> PredefinedTagMappings { get; } =
-            new Dictionary<string, Type>
-            {
-                { "tag:yaml.org,2002:map", typeof(Dictionary<object, object>) },
-                { "tag:yaml.org,2002:bool", typeof(bool) },
-                { "tag:yaml.org,2002:float", typeof(double) },
-                { "tag:yaml.org,2002:int", typeof(int) },
-                { "tag:yaml.org,2002:str", typeof(string) },
-                { "tag:yaml.org,2002:timestamp", typeof(DateTime) },
-            };
-
-        private readonly Dictionary<string, Type> _tagMappings;
+        private static Dictionary<TagName, Type> PredefinedTagMappings { get; } = new Dictionary<TagName, Type>
+        {
+            { "tag:yaml.org,2002:map", typeof(Dictionary<object, object>) },
+            { "tag:yaml.org,2002:bool", typeof(bool) },
+            { "tag:yaml.org,2002:float", typeof(double) },
+            { "tag:yaml.org,2002:int", typeof(int) },
+            { "tag:yaml.org,2002:str", typeof(string) },
+            { "tag:yaml.org,2002:timestamp", typeof(DateTime) },
+        };
+
+        private readonly Dictionary<TagName, Type> _tagMappings;
         private readonly List<IYamlTypeConverter> _converters;
-        private readonly TypeDescriptorProxy _typeDescriptor =
-            new TypeDescriptorProxy();
+        private readonly TypeDescriptorProxy _typeDescriptor = new TypeDescriptorProxy();
         private readonly IValueDeserializer _valueDeserializer;
 
         public IList<INodeDeserializer> NodeDeserializers { get; private set; }
@@ -103,7 +101,7 @@ public YamlDeserializer(
                 new EnumerableNodeDeserializer(),
                 new ExtensibleObjectNodeDeserializer(objectFactory, _typeDescriptor, ignoreUnmatched)
             };
-            _tagMappings = new Dictionary<string, Type>(PredefinedTagMappings);
+            _tagMappings = new Dictionary<TagName, Type>(PredefinedTagMappings);
             TypeResolvers = new List<INodeTypeResolver>
             {
                 new TagNodeTypeResolver(_tagMappings),
@@ -219,7 +217,7 @@ public LooseAliasValueDeserializer(IValueDeserializer innerDeserializer)
                 _innerDeserializer = innerDeserializer ?? throw new ArgumentNullException("innerDeserializer");
             }
 
-            private sealed class AliasState : Dictionary<string, ValuePromise>, IPostDeserializationCallback
+            private sealed class AliasState : Dictionary<AnchorName, ValuePromise>, IPostDeserializationCallback
             {
                 public void OnDeserialization()
                 {
@@ -295,10 +293,10 @@ public object DeserializeValue(IParser reader, Type expectedType, SerializerStat
                     return valuePromise.HasValue ? valuePromise.Value : valuePromise;
                 }
 
-                string anchor = null;
+                AnchorName? anchor = null;
 
                 var nodeEvent = reader.Peek<NodeEvent>();
-                if (nodeEvent != null && !string.IsNullOrEmpty(nodeEvent.Anchor))
+                if (nodeEvent != null && !nodeEvent.Anchor.IsEmpty)
                 {
                     anchor = nodeEvent.Anchor;
                 }
@@ -309,9 +307,9 @@ public object DeserializeValue(IParser reader, Type expectedType, SerializerStat
                 {
                     var aliasState = state.Get<AliasState>();
 
-                    if (!aliasState.TryGetValue(anchor, out ValuePromise valuePromise))
+                    if (!aliasState.TryGetValue(anchor.Value, out ValuePromise valuePromise))
                     {
-                        aliasState.Add(anchor, new ValuePromise(value));
+                        aliasState.Add(anchor.Value, new ValuePromise(value));
                     }
                     else if (!valuePromise.HasValue)
                     {
@@ -319,7 +317,7 @@ public object DeserializeValue(IParser reader, Type expectedType, SerializerStat
                     }
                     else
                     {
-                        aliasState[anchor] = new ValuePromise(value);
+                        aliasState[anchor.Value] = new ValuePromise(value);
                     }
                 }
 
@@ -327,4 +325,4 @@ public object DeserializeValue(IParser reader, Type expectedType, SerializerStat
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Microsoft.DocAsCode.YamlSerialization/YamlSerializer.cs b/src/Microsoft.DocAsCode.YamlSerialization/YamlSerializer.cs
index 3189f5a4111..2e1ce116b4c 100644
--- a/src/Microsoft.DocAsCode.YamlSerialization/YamlSerializer.cs
+++ b/src/Microsoft.DocAsCode.YamlSerialization/YamlSerializer.cs
@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using Microsoft.DocAsCode.YamlSerialization.ObjectGraphVisitors;
+
 namespace Microsoft.DocAsCode.YamlSerialization
 {
     using System;
@@ -90,14 +92,14 @@ private IObjectGraphVisitor<IEmitter> CreateEmittingVisitor(IEmitter emitter, IO
             if (!IsOptionSet(SerializationOptions.DisableAliases))
             {
                 var anchorAssigner = new AnchorAssigner(Converters);
-                traversalStrategy.Traverse<Nothing>(graph, anchorAssigner, null);
+                traversalStrategy.Traverse<Nothing>(graph, anchorAssigner, default);
 
                 emittingVisitor = new AnchorAssigningObjectGraphVisitor(emittingVisitor, eventEmitter, anchorAssigner);
             }
 
             if (!IsOptionSet(SerializationOptions.EmitDefaults))
             {
-                emittingVisitor = new DefaultExclusiveObjectGraphVisitor(emittingVisitor);
+                emittingVisitor = new ExclusiveObjectGraphVisitor(emittingVisitor);
             }
 
             return emittingVisitor;
@@ -130,7 +132,7 @@ private IEventEmitter CreateEventEmitter()
             }
             else
             {
-                return new TypeAssigningEventEmitter(writer, IsOptionSet(SerializationOptions.Roundtrip), new Dictionary<Type, string>());
+                return new TypeAssigningEventEmitter(writer, IsOptionSet(SerializationOptions.Roundtrip), new Dictionary<Type, TagName>());
             }
         }
 
@@ -156,3 +158,4 @@ private IObjectGraphTraversalStrategy CreateTraversalStrategy()
         }
     }
 }
+
diff --git a/test/Microsoft.DocAsCode.Build.TableOfContents.Tests/TocDocumentProcessorTest.cs b/test/Microsoft.DocAsCode.Build.TableOfContents.Tests/TocDocumentProcessorTest.cs
index 7ef39645b91..1e7ed264533 100644
--- a/test/Microsoft.DocAsCode.Build.TableOfContents.Tests/TocDocumentProcessorTest.cs
+++ b/test/Microsoft.DocAsCode.Build.TableOfContents.Tests/TocDocumentProcessorTest.cs
@@ -771,7 +771,7 @@ public void LoadBadTocYamlFileShouldGiveLineNumber()
       href: x2.md";
             var toc = _fileCreator.CreateFile(content, FileType.YamlToc);
             var ex = Assert.Throws<DocumentException>(() => TocHelper.LoadSingleToc(toc));
-            Assert.Equal("toc.yml is not a valid TOC File: toc.yml is not a valid TOC file, detail: (Line: 3, Col: 10, Idx: 22) - (Line: 3, Col: 10, Idx: 22): Mapping values are not allowed in this context..", ex.Message);
+            Assert.Equal("toc.yml is not a valid TOC File: toc.yml is not a valid TOC file, detail: (Line: 3, Col: 10, Idx: 22) - (Line: 3, Col: 10, Idx: 22): While scanning a plain scalar value, found invalid mapping..", ex.Message);
         }
 
         [Fact]