diff --git a/doc/monitor_modes.pdf b/doc/monitor_modes.pdf
deleted file mode 100644
index 64f2b10b28..0000000000
Binary files a/doc/monitor_modes.pdf and /dev/null differ
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 88270fe515..ee038563a5 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -6169,7 +6169,7 @@ Route::monitoring_state () const
 			break;
 	}
 
-	/* This is an implementation of the truth table in doc/monitor_modes.pdf;
+	/* This is an implementation of the truth table at https://manual.ardour.org/appendix/monitor-modes/
 	 * I don't think it's ever going to be too pretty too look at.
 	 */