diff --git a/Directory.Build.props b/Directory.Build.props
index 6c371ea..9a043fe 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -3,9 +3,6 @@
     <LangVersion>latest</LangVersion>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' != 'netstandard2.0' and !$(TargetFramework.StartsWith('netcoreapp2')) and !$(TargetFramework.StartsWith('net4'))">
-    <DefineConstants>$(DefineConstants);HAS_ASYNC_ENUMERATOR</DefineConstants>
-  </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="All" />
   </ItemGroup>
diff --git a/src/Ben.Demystifier/EnhancedStackTrace.Frames.cs b/src/Ben.Demystifier/EnhancedStackTrace.Frames.cs
index 705233c..95c8321 100644
--- a/src/Ben.Demystifier/EnhancedStackTrace.Frames.cs
+++ b/src/Ben.Demystifier/EnhancedStackTrace.Frames.cs
@@ -20,6 +20,24 @@ namespace System.Diagnostics
     public partial class EnhancedStackTrace
     {
         private static readonly Type? StackTraceHiddenAttributeType = Type.GetType("System.Diagnostics.StackTraceHiddenAttribute", false);
+        private static readonly Type? AsyncIteratorStateMachineAttributeType = Type.GetType("System.Runtime.CompilerServices.AsyncIteratorStateMachineAttribute", false);
+
+        static EnhancedStackTrace()
+        {
+            if (AsyncIteratorStateMachineAttributeType != null) return;
+
+            Assembly mba;
+            try
+            {
+                mba = Assembly.Load("Microsoft.Bcl.AsyncInterfaces");
+            }
+            catch
+            {
+                return;
+            }
+
+            AsyncIteratorStateMachineAttributeType = mba.GetType("System.Runtime.CompilerServices.AsyncIteratorStateMachineAttribute", false);
+        }
 
         private static List<EnhancedStackFrame> GetFrames(Exception exception)
         {
@@ -706,6 +724,10 @@ namespace System.Diagnostics
             {
                 return false;
             }
+            if (method.Name == "GetResult" && method.DeclaringType?.FullName == "System.Threading.Tasks.Sources.ManualResetValueTaskSourceCore`1")
+            {
+                return false;
+            }
             if (type == typeof(Task) || type.DeclaringType == typeof(Task))
             {
                 if (method.Name.Contains(".cctor"))
@@ -755,7 +777,7 @@ namespace System.Diagnostics
                     }
                 }
             }
-            
+
             if (type.Namespace == "Ply")
             {
                 if (type.DeclaringType?.Name == "TplPrimitives")
@@ -866,10 +888,8 @@ namespace System.Diagnostics
                     {
                         foundAttribute = true;
                         foundIteratorAttribute |= asma is IteratorStateMachineAttribute
-#if HAS_ASYNC_ENUMERATOR
-                            || asma is AsyncIteratorStateMachineAttribute
-#endif
-                            ;
+                            || AsyncIteratorStateMachineAttributeType != null
+                            && AsyncIteratorStateMachineAttributeType.IsInstanceOfType(asma);
                     }
                 }
 
diff --git a/test/Ben.Demystifier.Test/AsyncEnumerableTests.cs b/test/Ben.Demystifier.Test/AsyncEnumerableTests.cs
index 487ba27..26df76d 100644
--- a/test/Ben.Demystifier.Test/AsyncEnumerableTests.cs
+++ b/test/Ben.Demystifier.Test/AsyncEnumerableTests.cs
@@ -1,4 +1,3 @@
-#if HAS_ASYNC_ENUMERATOR
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -63,4 +62,3 @@ namespace Ben.Demystifier.Test
         }
     }
 }
-#endif
diff --git a/test/Ben.Demystifier.Test/Ben.Demystifier.Test.csproj b/test/Ben.Demystifier.Test/Ben.Demystifier.Test.csproj
index fc3126a..04286eb 100644
--- a/test/Ben.Demystifier.Test/Ben.Demystifier.Test.csproj
+++ b/test/Ben.Demystifier.Test/Ben.Demystifier.Test.csproj
@@ -2,13 +2,14 @@
   
   <PropertyGroup>
     <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
-    <TargetFrameworks Condition="'$(OS)' == 'Windows_NT'">$(TargetFrameworks);net46</TargetFrameworks>
+    <TargetFrameworks Condition="'$(OS)' == 'Windows_NT'">$(TargetFrameworks);net461</TargetFrameworks>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\src\Ben.Demystifier\key.snk</AssemblyOriginatorKeyFile>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="5.0.0" Condition="'$(TargetFramework)' == 'net461' or '$(TargetFramework)' == 'netcoreapp2.1'" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     <PackageReference Include="xunit" Version="2.4.1" />