diff --git a/src/RazorBlade.Library/RazorTemplate.cs b/src/RazorBlade.Library/RazorTemplate.cs
index c5ca3e9..e64bcef 100644
--- a/src/RazorBlade.Library/RazorTemplate.cs
+++ b/src/RazorBlade.Library/RazorTemplate.cs
@@ -182,7 +182,7 @@ protected internal virtual void Write(IEncodedContent? content)
     [EditorBrowsable(EditorBrowsableState.Never)]
     protected internal void DefineSection(string name, Func<Task> action)
     {
-#if NETCOREAPP
+#if NET6_0_OR_GREATER
         if (!_sections.TryAdd(name, action))
             throw new InvalidOperationException($"Section '{name}' is already defined.");
 #else