upgrade correction

Author: Sam Kleinman

source/release-notes/2.4-upgrade.txt

@@ -6,15 +6,15 @@ Upgrade MongoDB 2.2 to 2.4
 
 Only upgrade sharded clusters to 2.4 if all members of the cluster are
 currently running instances of 2.2. The only supported upgrade path
-for sharded clusters running 2.0 is via 2.2. 
+for sharded clusters running 2.0 is via 2.2.
 
 .. _upgrade-cluster-upgrade:
 
 Upgrade a Sharded Cluster from MongoDB 2.2 to MongoDB 2.4
 ---------------------------------------------------------
 
 Upgrading a :term:`sharded cluster` from MongoDB version 2.2 to 2.4
-(or 2.3) requires that you run a 2.4 :ref:`config server <sharding-config-server>`
+(or 2.3) requires that you run a 2.4 :program:`mongos`
 with the :option:`--upgrade <mongos --upgrade>` option, described in
 this procedure. The upgrade process does not require downtime.
 
@@ -30,8 +30,8 @@ collection metadata. For example, you cannot perform operations that
 add shards, drop databases, or drop collections, or modify the
 metadata in any other way.
 
-.. warning:: 
-   
+.. warning::
+
    Once you upgrade to 2.4 and complete the upgrade procedure **do
    not** use 2.0 :program:`mongod` and :program:`mongos` processes in
    your cluster. 2.0 process may re-introduce old metadata formats