DOCS-290: minor changes in response to feedback.

Author: Sam Kleinman

source/release-notes/2.2.txt

@@ -123,7 +123,7 @@ resources for background on the aggregation framework and its use:
 TTL Collections
 ```````````````
 
-TTL collections remove stale data from a collection, using a special
+TTL collections remove expired data from a collection, using a special
 index and a background thread that deletes expired documents every
 minute. These collections are useful as an alternative to
 :term:`capped collections <capped collection>` in some cases, for data
@@ -136,19 +136,18 @@ For more information, see the :doc:`/tutorial/expire-data` tutorial.
 Concurrency Improvements
 ````````````````````````
 
-In 2.2 MongoDB increases the database's capability for concurrent
-operations using with two key improvements:
+In 2.2 MongoDB increases the server's capacity for concurrent
+operations with two key improvements:
 
 #. :issue:`DB Level Locking <SERVER-4328>`
 #. :issue:`Improved Yielding on Page Faults <SERVER-3357>`
 
-To reflect these changes, MognODB now provides changed and improved
+To reflect these changes, MongoDB now provides changed and improved
 reporting for concurrency and use, see the :ref:`locks` and
 :ref:`server-status-record-stats` in :doc:`server status
 </reference/server-status>` and in the output of
 :func:`db.currentOp()` as well as :doc:`mongotop
-</reference/mongotop>` and :doc:`mongostat </reference/mongostat>` and
-in .
+</reference/mongotop>` and :doc:`mongostat </reference/mongostat>`.
 
 .. TODO add links to current op output documentation when it happens.
 
@@ -167,8 +166,8 @@ preferences <replica-set-read-preference>` including consistent
 support for a full range of :ref:`read preference modes
 <replica-set-read-preference-modes>` and :ref:`tag sets
 <replica-set-read-preference-tag-sets>`. This support extends to the
-:program:`mongos` and applies similarly to both single replica sets,
-and replica sets that provide components of a shard cluster.
+:program:`mongos` and applies identically to single replica sets, and
+the replica sets for each shard in a :term:`shard cluster`.
 
 Additional read preference support now exists in the :program:`mongo`
 shell using the :func:`reaPref() <cursor.readPref()>` cursor method.
@@ -185,14 +184,17 @@ In order to provide more reliable and robust support for
 authentication clients, including drivers and :program:`mongos`
 instances.
 
-If your :program:`mongod` instances or cluster is running with
+If your :program:`mongod` instances or cluster runs with
 authentication:
 
 - In sharded environments, 2.0 version :program:`mongos` instances are
   **not** compatible with 2.2 shard clusters running with
-  authentication. Use the :ref:`upgrade procedure for shard clusters
+  authentication.
+
+  You **must** use the :ref:`upgrade procedure for shard clusters
   <2.2-upgrade-shard-cluster>` and upgrade all :program:`mongos`
-  instances to prevent operational difficulty.
+  instances *before* upgrading the shard to prevent rendering your
+  cluster non-operational.
 
 - For all drivers, use the latest release of your driver and check
   its release notes.