diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
index eeeaf63bc8..a771f89878 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowBuilderExtensions.cs
@@ -114,7 +114,11 @@ public static class WorkflowBuilderExtensions
 
         Func<object?, bool> predicate = WorkflowBuilder.CreateConditionFunc<TMessage>((Func<object?, bool>)IsAllowedType)!;
 
+#if NET6_0_OR_GREATER
         if (targets.TryGetNonEnumeratedCount(out int count) && count == 1)
+#else
+        if (targets is ICollection<ExecutorBinding> { Count: 1 })
+#endif
         {
             return builder.AddEdge(source, Throw.IfNull(targets.First(), nameof(targets)), predicate);
         }