diff --git a/EnvelopeGenerator.API/Program.cs b/EnvelopeGenerator.API/Program.cs
index b7f53299..321e1c12 100644
--- a/EnvelopeGenerator.API/Program.cs
+++ b/EnvelopeGenerator.API/Program.cs
@@ -290,7 +290,9 @@ try
 
     app.UseMiddleware<ExceptionHandlingMiddleware>();
 
+#if NET9_0_OR_GREATER
     app.MapOpenApi();
+#endif
 
     // Configure the HTTP request pipeline.
     if (app.Environment.IsDevelopment() || (app.IsDevOrDiP() && config.GetValue<bool>("UseSwagger")))