diff --git a/doc/main.h b/doc/main.h
index 559c6b3f2..d4bde1b67 100644
--- a/doc/main.h
+++ b/doc/main.h
@@ -17,7 +17,7 @@
  *
  * \section install-sec Building the Documentation
  * 
- * ns-3 requires Doxygen version 1.8.3.1 or greater.
+ * Building ns-3 Doxygen requires Doxygen version 1.8 at a minimum, but version 1.9 is recommended to minimize warnings.
  * 
  * Type "./ns3 docs doxygen" or "./ns3 docs doxygen-no-build" to build the
  *  documentation.  The doc/ directory contains