diff --git a/v2rayN/v2rayN/Common/HttpClientHelper.cs b/v2rayN/v2rayN/Common/HttpClientHelper.cs
index 7b623e96..8f541c99 100644
--- a/v2rayN/v2rayN/Common/HttpClientHelper.cs
+++ b/v2rayN/v2rayN/Common/HttpClientHelper.cs
@@ -76,13 +76,13 @@ namespace v2rayN
                     //if (progressPercentage != percent && percent % 10 == 0)
                     {
                         progressPercentage = percent;
-                        progress!.Report(percent);
+                        progress?.Report(percent);
                     }
                 }
             }
             if (canReportProgress)
             {
-                progress!.Report(101);
+                progress?.Report(101);
             }
         }
 
diff --git a/v2rayN/v2rayN/Handler/LazyConfig.cs b/v2rayN/v2rayN/Handler/LazyConfig.cs
index 1b13a035..9a7a66e2 100644
--- a/v2rayN/v2rayN/Handler/LazyConfig.cs
+++ b/v2rayN/v2rayN/Handler/LazyConfig.cs
@@ -206,7 +206,7 @@ namespace v2rayN.Handler
             {
                 InitCoreInfo();
             }
-            return coreInfo!.FirstOrDefault(t => t.coreType == coreType);
+            return coreInfo?.FirstOrDefault(t => t.coreType == coreType);
         }
 
         public List<CoreInfo> GetCoreInfo()
diff --git a/v2rayN/v2rayN/Handler/UpdateHandle.cs b/v2rayN/v2rayN/Handler/UpdateHandle.cs
index 6304942b..5d7a50df 100644
--- a/v2rayN/v2rayN/Handler/UpdateHandle.cs
+++ b/v2rayN/v2rayN/Handler/UpdateHandle.cs
@@ -270,7 +270,7 @@ namespace v2rayN.Handler
                     else
                     {
                         _updateFunc(false, $"{hashCode}{ResUI.MsgGetSubscriptionSuccessfully}");
-                        if (result!.Length < 99)
+                        if (result?.Length < 99)
                         {
                             _updateFunc(false, $"{hashCode}{result}");
                         }
@@ -415,9 +415,9 @@ namespace v2rayN.Handler
             try
             {
                 var gitHubReleases = JsonUtile.Deserialize<List<GitHubRelease>>(gitHubReleaseApi);
-                var gitHubRelease = preRelease ? gitHubReleases!.First() : gitHubReleases!.First(r => r.Prerelease == false);
-                var version = new SemanticVersion(gitHubRelease!.TagName);
-                var body = gitHubRelease!.Body;
+                var gitHubRelease = preRelease ? gitHubReleases?.First() : gitHubReleases?.First(r => r.Prerelease == false);
+                var version = new SemanticVersion(gitHubRelease?.TagName!);
+                var body = gitHubRelease?.Body;
 
                 var coreInfo = LazyConfig.Instance.GetCoreInfo(type);
 
diff --git a/v2rayN/v2rayN/Model/SingboxConfig.cs b/v2rayN/v2rayN/Model/SingboxConfig.cs
index 1e46e24b..ff01457b 100644
--- a/v2rayN/v2rayN/Model/SingboxConfig.cs
+++ b/v2rayN/v2rayN/Model/SingboxConfig.cs
@@ -3,7 +3,7 @@
     public class SingboxConfig
     {
         public Log4Sbox log { get; set; }
-        public object dns { get; set; }
+        public Dns4Sbox? dns { get; set; }
         public List<Inbound4Sbox> inbounds { get; set; }
         public List<Outbound4Sbox> outbounds { get; set; }
         public Route4Sbox route { get; set; }
@@ -186,7 +186,7 @@
         public string address { get; set; }
         public string address_resolver { get; set; }
         public string strategy { get; set; }
-        public string detour { get; set; }
+        public string? detour { get; set; }
     }
 
     public class Experimental4Sbox