diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 6a8fd021b9f..ba0225ba2b6 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -265,6 +265,9 @@ options 	COMPAT_43
 # Enable FreeBSD4 compatibility syscalls
 options 	COMPAT_FREEBSD4
 
+# Enable FreeBSD5 compatibility syscalls
+options 	COMPAT_FREEBSD5
+
 #
 # These three options provide support for System V Interface
 # Definition-style interprocess communication, in the form of shared