Update xenserver.rst
diff --git a/source/installguide/hypervisor/xenserver.rst b/source/installguide/hypervisor/xenserver.rst
index 8cd3499..9a24689 100644
--- a/source/installguide/hypervisor/xenserver.rst
+++ b/source/installguide/hypervisor/xenserver.rst
@@ -34,8 +34,8 @@
     -  XenServer 7.0 
     -  XenServer 7.1
     -  XenServer 7.5
-    -  XenServer 8.0
-    -  XenServer 8.1
+    -  XenServer 8.0 (not tested explicitly, but should work - see the release notes)
+    -  XenServer 8.1 (not tested explicitly, but should work - see the release notes)
     -  XCP-ng 7.4.0
     -  XCP-ng 7.5.0
     -  XCP-ng 7.6.0