--- wikisrc/ports/xen/howto.mdwn	2016/12/21 16:57:10	1.135
+++ wikisrc/ports/xen/howto.mdwn	2016/12/21 17:03:03	1.136
@@ -126,7 +126,8 @@ xenkernel46 provides Xen 4.6.  It is new
 of 2016-12, security patches were released by Xen and applied to
 pkgsrc.  Xen 4.6 runs on amd64 hardware only For new installations,
 4.6 is probably the appropriate choice and it will likely soon be the
-standard approach.
+standard approach.  (If using Ubuntu guests, be sure to have the
+xentools46 from December, 2016).
 
 Xen 4.7 (released 2016-06) and 4.8 (released 2016-12) are not yet in
 pkgsrc.
@@ -243,6 +244,14 @@ xl, the NetBSD 7 stable branch, and to u
 dom0.  Either the i386PAE or amd64 version of NetBSD may be used as
 domUs.
 
+Because bugs are fixed quite often, and because of Xen security
+advisories, it is good to stay up to date with NetBSD (tracking a
+stable branch), with the Xen kernel (tracking a Xen version via
+pkgsrc), and with the Xen tools.  Specifically, NetBSD (-7 and
+-current) got an important fix affecting dom0/domU timesharing in
+November, 2015, and xentools46 got a fix to enable Ubuntu guests to
+boot in December, 2016.
+
 Status
 ------