diff --git a/framework/src/Volo.Abp.Auditing/Volo.Abp.Auditing.csproj b/framework/src/Volo.Abp.Auditing/Volo.Abp.Auditing.csproj
index 6a29572457..00abec3b37 100644
--- a/framework/src/Volo.Abp.Auditing/Volo.Abp.Auditing.csproj
+++ b/framework/src/Volo.Abp.Auditing/Volo.Abp.Auditing.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Auditing</AssemblyName>
     <PackageId>Volo.Abp.Auditing</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AbpAuditingOptions.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AbpAuditingOptions.cs
index 623733e8e5..30b32c3587 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AbpAuditingOptions.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AbpAuditingOptions.cs
@@ -26,7 +26,7 @@ public class AbpAuditingOptions
     /// The name of the application or service writing audit logs.
     /// Default: null.
     /// </summary>
-    public string ApplicationName { get; set; }
+    public string? ApplicationName { get; set; }
 
     /// <summary>
     /// Default: true.
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogActionInfo.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogActionInfo.cs
index e312f947e4..f9f2c66cd0 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogActionInfo.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogActionInfo.cs
@@ -7,11 +7,11 @@ namespace Volo.Abp.Auditing;
 [Serializable]
 public class AuditLogActionInfo : IHasExtraProperties
 {
-    public string ServiceName { get; set; }
+    public string ServiceName { get; set; } = default!;
 
-    public string MethodName { get; set; }
+    public string MethodName { get; set; } = default!;
 
-    public string Parameters { get; set; }
+    public string Parameters { get; set; } = default!;
 
     public DateTime ExecutionTime { get; set; }
 
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogInfo.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogInfo.cs
index 4df472da24..962b143e8c 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogInfo.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditLogInfo.cs
@@ -9,43 +9,43 @@ namespace Volo.Abp.Auditing;
 [Serializable]
 public class AuditLogInfo : IHasExtraProperties
 {
-    public string ApplicationName { get; set; }
+    public string? ApplicationName { get; set; }
 
     public Guid? UserId { get; set; }
 
-    public string UserName { get; set; }
+    public string? UserName { get; set; }
 
     public Guid? TenantId { get; set; }
 
-    public string TenantName { get; set; }
+    public string? TenantName { get; set; }
 
     public Guid? ImpersonatorUserId { get; set; }
 
     public Guid? ImpersonatorTenantId { get; set; }
 
-    public string ImpersonatorUserName { get; set; }
+    public string? ImpersonatorUserName { get; set; }
 
-    public string ImpersonatorTenantName { get; set; }
+    public string? ImpersonatorTenantName { get; set; }
 
     public DateTime ExecutionTime { get; set; }
 
     public int ExecutionDuration { get; set; }
 
-    public string ClientId { get; set; }
+    public string? ClientId { get; set; }
 
-    public string CorrelationId { get; set; }
+    public string? CorrelationId { get; set; }
 
-    public string ClientIpAddress { get; set; }
+    public string? ClientIpAddress { get; set; }
 
-    public string ClientName { get; set; }
+    public string? ClientName { get; set; }
 
-    public string BrowserInfo { get; set; }
+    public string? BrowserInfo { get; set; }
 
-    public string HttpMethod { get; set; }
+    public string? HttpMethod { get; set; }
 
     public int? HttpStatusCode { get; set; }
 
-    public string Url { get; set; }
+    public string? Url { get; set; }
 
     public List<AuditLogActionInfo> Actions { get; set; }
 
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingHelper.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingHelper.cs
index 7468f10986..aadbeccabb 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingHelper.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingHelper.cs
@@ -52,7 +52,7 @@ public class AuditingHelper : IAuditingHelper, ITransientDependency
         CorrelationIdProvider = correlationIdProvider;
     }
 
-    public virtual bool ShouldSaveAudit(MethodInfo methodInfo, bool defaultValue = false, bool ignoreIntegrationServiceAttribute = false)
+    public virtual bool ShouldSaveAudit(MethodInfo? methodInfo, bool defaultValue = false, bool ignoreIntegrationServiceAttribute = false)
     {
         if (methodInfo == null)
         {
@@ -150,23 +150,23 @@ public class AuditingHelper : IAuditingHelper, ITransientDependency
 
     public virtual AuditLogActionInfo CreateAuditLogAction(
         AuditLogInfo auditLog,
-        Type type,
+        Type? type,
         MethodInfo method,
-        object[] arguments)
+        object?[] arguments)
     {
         return CreateAuditLogAction(auditLog, type, method, CreateArgumentsDictionary(method, arguments));
     }
 
     public virtual AuditLogActionInfo CreateAuditLogAction(
         AuditLogInfo auditLog,
-        Type type,
+        Type? type,
         MethodInfo method,
-        IDictionary<string, object> arguments)
+        IDictionary<string, object?> arguments)
     {
         var actionInfo = new AuditLogActionInfo
         {
             ServiceName = type != null
-                ? type.FullName
+                ? type.FullName!
                 : "",
             MethodName = method.Name,
             Parameters = SerializeConvertArguments(arguments),
@@ -198,7 +198,7 @@ public class AuditingHelper : IAuditingHelper, ITransientDependency
         }
     }
 
-    protected virtual string SerializeConvertArguments(IDictionary<string, object> arguments)
+    protected virtual string SerializeConvertArguments(IDictionary<string, object?> arguments)
     {
         try
         {
@@ -207,7 +207,7 @@ public class AuditingHelper : IAuditingHelper, ITransientDependency
                 return "{}";
             }
 
-            var dictionary = new Dictionary<string, object>();
+            var dictionary = new Dictionary<string, object?>();
 
             foreach (var argument in arguments)
             {
@@ -230,14 +230,14 @@ public class AuditingHelper : IAuditingHelper, ITransientDependency
         }
     }
 
-    protected virtual Dictionary<string, object> CreateArgumentsDictionary(MethodInfo method, object[] arguments)
+    protected virtual Dictionary<string, object?> CreateArgumentsDictionary(MethodInfo method, object?[] arguments)
     {
         var parameters = method.GetParameters();
-        var dictionary = new Dictionary<string, object>();
+        var dictionary = new Dictionary<string, object?>();
 
         for (var i = 0; i < parameters.Length; i++)
         {
-            dictionary[parameters[i].Name] = arguments[i];
+            dictionary[parameters[i].Name!] = arguments[i];
         }
 
         return dictionary;
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingInterceptor.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingInterceptor.cs
index bee71b723a..6be28d24cf 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingInterceptor.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingInterceptor.cs
@@ -80,7 +80,7 @@ public class AuditingInterceptor : AbpInterceptor, ITransientDependency
     {
         var auditLog = auditLogScope.Log;
 
-        AuditLogActionInfo auditLogAction = null;
+        AuditLogActionInfo? auditLogAction = null;
         if (!options.DisableLogActionInfo)
         {
             auditLogAction = auditingHelper.CreateAuditLogAction(
@@ -127,10 +127,10 @@ public class AuditingInterceptor : AbpInterceptor, ITransientDependency
         {
             try
             {
-                await ProceedByLoggingAsync(invocation, options, auditingHelper, auditingManager.Current);
+                await ProceedByLoggingAsync(invocation, options, auditingHelper, auditingManager.Current!);
 
                 Debug.Assert(auditingManager.Current != null);
-                if (auditingManager.Current.Log.Exceptions.Any())
+                if (auditingManager.Current!.Log.Exceptions.Any())
                 {
                     hasError = true;
                 }
@@ -142,7 +142,7 @@ public class AuditingInterceptor : AbpInterceptor, ITransientDependency
             }
             finally
             {
-                if (await ShouldWriteAuditLogAsync(invocation, auditingManager.Current.Log, options, currentUser, hasError))
+                if (await ShouldWriteAuditLogAsync(invocation, auditingManager.Current!.Log, options, currentUser, hasError))
                 {
                     if (unitOfWorkManager.Current != null)
                     {
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingManager.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingManager.cs
index 43d86825ec..df6c435de1 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingManager.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/AuditingManager.cs
@@ -38,7 +38,7 @@ public class AuditingManager : IAuditingManager, ITransientDependency
         _auditingStore = auditingStore;
     }
 
-    public IAuditLogScope Current => _ambientScopeProvider.GetValue(AmbientContextKey);
+    public IAuditLogScope? Current => _ambientScopeProvider.GetValue(AmbientContextKey);
 
     public IAuditLogSaveHandle BeginScope()
     {
@@ -49,7 +49,7 @@ public class AuditingManager : IAuditingManager, ITransientDependency
 
         Debug.Assert(Current != null, "Current != null");
 
-        return new DisposableSaveHandle(this, ambientScope, Current.Log, Stopwatch.StartNew());
+        return new DisposableSaveHandle(this, ambientScope, Current!.Log, Stopwatch.StartNew());
     }
 
     protected virtual void ExecutePostContributors(AuditLogInfo auditLogInfo)
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityChangeInfo.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityChangeInfo.cs
index 9ed4114e48..261809a968 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityChangeInfo.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityChangeInfo.cs
@@ -19,15 +19,15 @@ public class EntityChangeInfo : IHasExtraProperties
     /// </summary>
     public Guid? EntityTenantId { get; set; }
 
-    public string EntityId { get; set; }
+    public string? EntityId { get; set; }
 
-    public string EntityTypeFullName { get; set; }
+    public string? EntityTypeFullName { get; set; }
 
-    public List<EntityPropertyChangeInfo> PropertyChanges { get; set; }
+    public List<EntityPropertyChangeInfo> PropertyChanges { get; set; } = default!;
 
     public ExtraPropertyDictionary ExtraProperties { get; }
 
-    public virtual object EntityEntry { get; set; } //TODO: Try to remove since it breaks serializability
+    public virtual object EntityEntry { get; set; } = default!; //TODO: Try to remove since it breaks serializability
 
     public EntityChangeInfo()
     {
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityPropertyChangeInfo.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityPropertyChangeInfo.cs
index 5e92f6622e..e25369d7b2 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityPropertyChangeInfo.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/EntityPropertyChangeInfo.cs
@@ -23,11 +23,11 @@ public class EntityPropertyChangeInfo
     /// </summary>
     public static int MaxPropertyTypeFullNameLength = 192;
 
-    public virtual string NewValue { get; set; }
+    public virtual string? NewValue { get; set; }
 
-    public virtual string OriginalValue { get; set; }
+    public virtual string? OriginalValue { get; set; }
 
-    public virtual string PropertyName { get; set; }
+    public virtual string PropertyName { get; set; } = default!;
 
-    public virtual string PropertyTypeFullName { get; set; }
+    public virtual string PropertyTypeFullName { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingHelper.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingHelper.cs
index 5a2878d1b0..e6fa20bc90 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingHelper.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingHelper.cs
@@ -7,7 +7,7 @@ namespace Volo.Abp.Auditing;
 //TODO: Move ShouldSaveAudit & IsEntityHistoryEnabled and rename to IAuditingFactory
 public interface IAuditingHelper
 {
-    bool ShouldSaveAudit(MethodInfo methodInfo, bool defaultValue = false, bool ignoreIntegrationServiceAttribute = false);
+    bool ShouldSaveAudit(MethodInfo? methodInfo, bool defaultValue = false, bool ignoreIntegrationServiceAttribute = false);
 
     bool IsEntityHistoryEnabled(Type entityType, bool defaultValue = false);
 
@@ -15,15 +15,15 @@ public interface IAuditingHelper
 
     AuditLogActionInfo CreateAuditLogAction(
         AuditLogInfo auditLog,
-        Type type,
+        Type? type,
         MethodInfo method,
-        object[] arguments
+        object?[] arguments
     );
 
     AuditLogActionInfo CreateAuditLogAction(
         AuditLogInfo auditLog,
-        Type type,
+        Type? type,
         MethodInfo method,
-        IDictionary<string, object> arguments
+        IDictionary<string, object?> arguments
     );
 }
diff --git a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingManager.cs b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingManager.cs
index 35a465396d..a1091b8600 100644
--- a/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingManager.cs
+++ b/framework/src/Volo.Abp.Auditing/Volo/Abp/Auditing/IAuditingManager.cs
@@ -4,8 +4,7 @@ namespace Volo.Abp.Auditing;
 
 public interface IAuditingManager
 {
-    [CanBeNull]
-    IAuditLogScope Current { get; }
+    IAuditLogScope? Current { get; }
 
     IAuditLogSaveHandle BeginScope();
 }
diff --git a/framework/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/EntityHistory/EntityHistoryHelper.cs b/framework/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/EntityHistory/EntityHistoryHelper.cs
index 801e772e26..d21e4c43c5 100644
--- a/framework/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/EntityHistory/EntityHistoryHelper.cs
+++ b/framework/src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/EntityHistory/EntityHistoryHelper.cs
@@ -177,10 +177,10 @@ public class EntityHistoryHelper : IEntityHistoryHelper, ITransientDependency
             {
                 propertyChanges.Add(new EntityPropertyChangeInfo
                 {
-                    NewValue = isDeleted ? null : JsonSerializer.Serialize(propertyEntry.CurrentValue).TruncateWithPostfix(EntityPropertyChangeInfo.MaxValueLength),
-                    OriginalValue = isCreated ? null : JsonSerializer.Serialize(propertyEntry.OriginalValue).TruncateWithPostfix(EntityPropertyChangeInfo.MaxValueLength),
+                    NewValue = isDeleted ? null : JsonSerializer.Serialize(propertyEntry.CurrentValue!).TruncateWithPostfix(EntityPropertyChangeInfo.MaxValueLength),
+                    OriginalValue = isCreated ? null : JsonSerializer.Serialize(propertyEntry.OriginalValue!).TruncateWithPostfix(EntityPropertyChangeInfo.MaxValueLength),
                     PropertyName = property.Name,
-                    PropertyTypeFullName = property.ClrType.GetFirstGenericArgumentIfNullable().FullName
+                    PropertyTypeFullName = property.ClrType.GetFirstGenericArgumentIfNullable().FullName!
                 });
             }
         }