(DOCSP-35387): Clarify new accepted value for mms.userSvcClass parameter (#34)

[Jira](https://jira.mongodb.org/browse/DOCSP-35387)

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Author: davidhou17

source/includes/setting-fileConf-mms.userSvcClass.rst

@@ -23,10 +23,11 @@
 
           .. important::
 
-             If you use the old accepted value,
-             ``UserSvcDb``, your |mms|
+             In |onprem| 6.0, the accepted value is 
+             ``com.xgen.svc.mms.svc.user.UserSvcDb``. 
+             If you use this old accepted value, your |mms|
              instance will not start during preflight checks.
-   
+              
       * - |ldap|
         - ``UserSvcLdap``
 

source/release-notes/release-advisories/advisories-v7.0.rst

@@ -66,3 +66,16 @@ User Interface
 ~~~~~~~~~~~~~~
 
 - Removes support for Internet Explorer 11.
+
+Configuration Setting Changes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Updates the accepted value that represents the Application 
+  Database authentication method for the :setting:`mms.userSvcClass` 
+  setting from ``com.xgen.svc.mms.svc.user.UserSvcDb`` to 
+  ``com.xgen.cloud.user._private.svc.UserSvcDb``. 
+
+  .. important:: 
+
+     If you use the old accepted value, ``com.xgen.svc.mms.svc.user.UserSvcDb``, 
+     your |mms| instance will not start during preflight checks.