Update upgrade-4.11.rst

reword warning

Author: Paul Angus

source/upgrading/upgrade/upgrade-4.11.rst

@@ -50,14 +50,17 @@ Overview of Upgrade Steps:
 .. include:: _customisation_warnings.rst
 
 .. warning::
-    If you are not already using the |sysvm64-version| System VM template you will need to 
-    upgrade your System VM template prior to performing the upgrade of the 
-    CloudStack packages.
+    If you have not registered the 4.11.3 System VM templates for your hypervisors,
+    you will need to register them prior to performing the upgrade of the CloudStack
+    packages. This includes those currently running a **clean** install of CloudStack 4.11.3 (ie you
+    did not upgrade from another version to reach 4.11.3), you will still need to 
+    explicitly register the 4.11.3 System VM template(s), you will not however need
+    to restart the existing system VMs. 
 
-.. warning::
-    Even if you are currently running a **clean** install of CloudStack 4.11.3, you will need to explicitely register the 
-    |sysvm64-version| System VM template. If you are running CloudStack 4.11.3 that was upgraded from some of the previous versions,
-    you don't need to register a new |sysvm64-version| System VM template.
+    If you are running an instance of CloudStack 4.11.3
+    that was upgraded from a the previous versions,
+    you will already have explicitly registered the 4.11.3 System VM template(s) and
+    need not do it again.
 
 .. include:: _sysvm_templates.rst