diff --git a/INSTALL b/INSTALL
index 0cb5ab992..27a5e6a0a 100644
--- a/INSTALL
+++ b/INSTALL
@@ -9,9 +9,10 @@ INSTALL NOTES
    other than /usr/local (ie: --prefix=/opt).
 
    NOTE: if you use C2 security you need to use the --with-C2 flag to
-   configure.  Currently this only affect hpux.  You can use --with-C2
-   if you are just expecting to migrate to C2 security later but it makes
-   password lookups about twice as slow.
+   configure.  Currently this only affects hpux and ConvexOS with
+   C@ security.  For hpux only, you can use --with-C2 if you are expecting
+   to migrate to C2 security later but it makes password lookups about
+   twice as slow.
 
 1) Read sudo.h to enable/disable the options you may or may not want.